So you decided to hold a contest on Codeforces. You prepared the problems: statements, solutions, checkers, validators, tests... Suddenly, your coordinator asks you to change all your tests to multiple testcases in the easiest problem!

Initially, each test in that problem is just an array. The maximum size of an array is k. For simplicity, the contents of arrays don't matter. You have n tests — the i-th test is an array of size m_i (1 ≤ m_i ≤ k).

Your coordinator asks you to distribute all of your arrays into multiple testcases. Each testcase can include multiple arrays. However, each testcase should include no more than c_1 arrays of size greater than or equal to 1 (≥ 1), no more than c_2 arrays of size greater than or equal to 2, ..., no more than c_k arrays of size greater than or equal to k. Also, c_1 ≥ c_2 ≥ ... ≥ c_k.

So now your goal is to create the new testcases in such a way that: 

  * each of the initial arrays appears in exactly one testcase; 
  * for each testcase the given conditions hold; 
  * the number of testcases is minimum possible. 



Print the minimum possible number of testcases you can achieve and the sizes of arrays included in each testcase.

Input

The first line contains two integers n and k (1 ≤ n, k ≤ 2 ⋅ 10^5) — the number of initial tests and the limit for the size of each array.

The second line contains n integers m_1, m_2, ..., m_n (1 ≤ m_i ≤ k) — the sizes of the arrays in the original tests.

The third line contains k integers c_1, c_2, ..., c_k (n ≥ c_1 ≥ c_2 ≥ ... ≥ c_k ≥ 1); c_i is the maximum number of arrays of size greater than or equal to i you can have in a single testcase.

Output

In the first line print a single integer ans (1 ≤ ans ≤ n) — the minimum number of testcases you can achieve.

Each of the next ans lines should contain the description of a testcase in the following format:

t a_1 a_2 ... a_{t} (1 ≤ t≤ n) — the testcase includes t arrays, a_i is the size of the i-th array in that testcase.

Each of the initial arrays should appear in exactly one testcase. In particular, it implies that the sum of t over all ans testcases should be equal to n.

Note that the answer always exists due to c_k ≥ 1 (and therefore c_1 ≥ 1).

If there are multiple answers, you can output any one of them.

Examples

Input


4 3
1 2 2 3
4 1 1


Output


3
1 2
2 1 3
1 2


Input


6 10
5 8 1 10 8 7
6 6 4 4 3 2 2 2 1 1


Output


2
3 8 5 7
3 10 8 1


Input


5 1
1 1 1 1 1
5


Output


1
5 1 1 1 1 1


Input


5 1
1 1 1 1 1
1


Output


5
1 1
1 1
1 1
1 1
1 1

Note

In the first example there is no way to distribute the tests into less than 3 testcases. The given answer satisfies the conditions: each of the testcases includes no more than 4 arrays of size greater than or equal to 1 and no more than 1 array of sizes greater than or equal to 2 and 3.

Note that there are multiple valid answers for this test. For example, testcases with sizes [[2], [1, 2], [3]] would also be correct.

However, testcases with sizes [[1, 2], [2, 3]] would be incorrect because there are 2 arrays of size greater than or equal to 2 in the second testcase.

Note the difference between the third and the fourth examples. You can include up to 5 arrays of size greater than or equal to 1 in the third example, so you can put all arrays into a single testcase. And you can have only up to 1 array in the fourth example. Thus, every array should be included in a separate testcase.
//package learning;
import java.util.*;
import java.io.*;
import java.lang.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;
public class NitsLocal {
    static ArrayList<String> s1;
    static boolean[] prime;
    static int n = 200001;
    
     static void sieve() {
Arrays.fill(prime	, true);
prime[0] = prime[1] = false;
for(int i = 2 ; i * i <= n ; ++i) {
if(prime[i]) {
for(int k = i * i; k<= n ; k+=i) {
prime[k] = false;
}
}
}
 
}
    public static void main(String[] args) {
        InputReader sc = new InputReader(System.in);
        
           //prime  = new boolean[n + 1];
          // sieve();
                //prime[1] = false;
              
                  
             /*    
        int n = sc.ni();
        int k = sc.ni();
        int []vis = new int[n+1];
        int []a = new int[k];
        for(int i=0;i<k;i++)
        {
            a[i] = i+1;
        }
        int j = k+1;
        int []b = new int[n+1];
        for(int i=1;i<=n;i++)
        {
            b[i] = -1;
        }
        int y = n - k +1;
        int tr = 0;
        int y1 = k+1;
        while(y-- > 0)
        {
        System.out.print("? ");
        for(int i=0;i<k;i++)
        {
            System.out.print(a[i] + " ");
        }
        
        System.out.flush();
        int pos = sc.ni();
        int a1 = sc.ni();
        b[pos] = a1;
        
        
        for(int i=0;i<k;i++)
        {
            if(a[i] == pos)
            {
                a[i] = y1;
                y1++;
            }
        }
        }
        ArrayList<Integer> a2 = new ArrayList<>();
        if(y >= k)
        {
            
        int c = 0;
        int k1 = 0;
            for(int i=1;i<=n;i++)
            {
                if(b[i] != -1)
                {
                    c++;
                    a[k1] = i;
                    a2.add(b[i]);
                    k1++;
                }
                if(c==k)
                    break;
            }
            
            Collections.sort(a2);
            System.out.print("? ");
        for(int i=0;i<k;i++)
        {
            System.out.print(a[i] + " ");
        }
        System.out.println();
        System.out.flush();
        int pos = sc.ni();
        int a1 = sc.ni();
        int ans = -1;
        for(int i=0;i<a2.size();i++)
        {
            if(a2.get(i) == a1)
            {
                ans = i+1;
                break;
            }
        }
        System.out.println("!" + " " + ans);
           System.out.flush();  
        }
        else
        {
            int k1 = 0;
            a = new int[k];
             for(int i=1;i<=n;i++)
            {
                if(b[i] != -1)
                {
                    
                    a[k1] = i;
                    a2.add(b[i]);
                    k1++;
                }
             
            }
              for(int i=1;i<=n;i++)
            {
                if(b[i] == -1)
                {
                    
                    a[k1] = i;
                    
                    k1++;
                    if(k1==k)
                        break;
                }
             
            }
              int ans = -1;
              while(true)
              {
                   System.out.print("? ");
                     for(int i=0;i<k;i++)
                   {
                         System.out.print(a[i] + " ");
                  }
                   System.out.println();
                   System.out.flush();
                   int pos = sc.ni();
                   int a1 = sc.ni();
                   int f = 0;
                   
                   if(b[pos] != -1)
                   {
                       Collections.sort(a2);
                       for(int i=0;i<a2.size();i++)
                       {
                           if(a2.get(i) == a1)
                           {
                               ans = i+1;
                               f = 1;
                               System.out.println("!" + " " + ans);
                               System.out.flush();
                               break;
                           }
                       }
                       if(f==1)
                           break;
                   }
                   else
                   {
                       b[pos] = a1;
                        a = new int[k];
                        a2.add(a1);
             for(int i=1;i<=n;i++)
            {
                if(b[i] != -1)
                {
                    
                    a[k1] = i;
                    a2.add(b[i]);
                    k1++;
                }
             
            }
              for(int i=1;i<=n;i++)
            {
                if(b[i] == -1)
                {
                    
                    a[k1] = i;
                    
                    k1++;
                    if(k1==k)
                        break;
                }
             
                       
                   }
              }
        }  
          */
             
 
    /*
          int n = sc.ni();
          int []a = sc.nia(n);
          int []b = sc.nia(n);
          Integer []d = new Integer[n];
          int []d1 = new int[n];
          for(int i=0;i<n;i++)
          {
              d[i] = (a[i] - b[i]);
             
          }
          int l = 0;
          int r = n-1;
          Arrays.sort(d);
          long res = 0;
          while(l < r)
          {
              if(d[l] + d[r] > 0)
              {
                  res += (long) (r-l);
                  r--;
              }
              else 
                  l++;
          }
          
          w.println(res);
*/
      /*
      int n = sc.ni();
     
      ArrayList<Integer> t1 = new ArrayList<>();
      int []p1 = new int[n+1];
      int []q1 = new int[n-1];
      int []q2 = new int[n-1];
      for(int i=0;i<n-1;i++)
      {
          int p = sc.ni();
          int q = sc.ni();
          t1.add(q);
          p1[p]++;
          q1[i] = p;
          q2[i] = q;
          
      }
      int res = 0;
      for(int i=0;i<t1.size();i++)
      {
          if(p1[t1.get(i)] == 0)
          {
              res = t1.get(i);
              //break;
          }
      }
      
    int y = 1;
    for(int i=0;i<n-1;i++)
    {
        if(q2[i] == res)
        {
            w.println("0");
        }
        else
        {
            w.println(y + " ");
            y++;
        }
    }
      */
 /*
   int n = sc.ni();
   int k = sc.ni();
   Integer []a = new Integer[n];
   for(int i=0;i<n;i++)
   {
       a[i] = sc.ni();
       a[i] = a[i]%k;
   }
   HashMap<Integer,Integer> hm = new HashMap<>();
   for(int i=0;i<n;i++)
   {
       if(!hm.containsKey(a[i]))
           hm.put(a[i], 1);
       else
           hm.put(a[i], hm.get(a[i]) + 1);
   }
  Arrays.sort(a);
  int z = 0;
  long res = 0;
  HashMap<Integer,Integer> v = new HashMap<>();
  for(int i=0;i<n;i++)
  {
      if(a[i] == 0)
          res++;
      else
      {
          if(a[i] == k-a[i] && !v.containsKey(a[i]))
          {
              res += (long) hm.get(a[i]) / 2;
              v.put(a[i],1);
          }
          else
          {
          if(hm.containsKey(a[i]) && hm.containsKey(k-a[i]))
          {
          int temp = a[i];
          
          if(!v.containsKey(a[i]) && !v.containsKey(k-a[i]))
          {
             res += (long) Math.min(hm.get(temp), hm.get(k-temp));
             v.put(temp,1);
             v.put(k-temp,1);
          }
          }
          }
      }
  }
  w.println(res);
*/
 /*
int []a = new int[4];
//G0
a[0] = 0;
a[1] = 1;
a[2] = 0;
a[3] = 1;
int []b = new int[4];
//g1
b[0] = 0;
b[1] = 1;
b[2] = 1;
b[3] = 0;
int [][]dp1 = new int[4][4];
int [][]dp2 = new int[4][4];
for(int i=0;i<4;i++)
{
    for(int j=0;j<4;j++)
    {
        dp1[i][j] = (a[i] | a[j]);
    }
   // w.println();
}
w.println();
for(int i=0;i<4;i++)
{
    for(int j=0;j<4;j++)
    {
        dp2[i][j] = (b[i] | b[j]);
    }
    //w.println();
}
int a1 = 0;
int b1 = 0;
int c1 = 0;
int d1 = 0;
for(int i=0;i<4;i++)
{
    for(int j=0;j<4;j++)
    {
        if(dp1[i][j] == 0 && dp2[i][j] == 0)
            a1++;
        else  if(dp1[i][j] == 1 && dp2[i][j] == 1)
            b1++;
        else  if(dp1[i][j] == 0 && dp2[i][j] == 1)
            c1++;
        else
            d1++;
       
    }
}
w.println(a1+ " " + b1 + " " + c1 +" "+ d1);

Scanner sc = new Scanner(System.in);
    int q = sc.nextInt();
    while(q-- > 0)
    {
        long x = sc.nextLong();
        long y = sc.nextLong();
        long a = (x - y)/2;  
        long a1 = 0, b1 = 0; 
        
        
        int lim     = 8; 
  
   
    int f = 0;
    
    for (int i=0; i<8*lim; i++)  
    {  
        long pi = (y & (1 << i));  
        long qi = (a & (1 << i));  
        if (pi == 0 && qi == 0)  
        {  
             
        }  
        else if (pi == 0 && qi > 0)  
        {  
            a1 = ((1 << i) | a1);  
            b1 = ((1 << i) | b1);  
        }  
        else if (pi > 0 && qi == 0)  
        {  
            a1 = ((1 << i) | a1);  
  
           
        }  
        else
        {  
            f = 1;  
            
        }  
    }  
    if(a1+b1 != x)
        f  =1;
  if(f==1)
            System.out.println("-1");
  else
  {
       if(a1 > b1)
       {
           long temp = a1;
           a1 = b1;
           b1 = temp;
       }
    System.out.println(a1 + " " + b1);
   
  }
  
  
    }
     
     */

     /*
    int n = sc.ni();
    int k = sc.ni();
    int []a = sc.nia(n);
    int []c = new int[n+1];
    int m = n;
    int f = 0;
    
        for(int i=0;i<k;i++)
        {
            c[a[i]]++;
        }
        HashSet<Integer> temp = new HashSet<>();
        for(int i=k;i<n;i++)
        {
            if(c[a[i]] == 0)
            {
                temp.add(a[i]);
            }
        }
        int re =  temp.size();
        int st = 0;
        if(re > 0)
        {
        for(int i=k-1;i>=0;i--)
        {
            
            c[a[i]]--;
            if(c[a[i]] == 0)
            {
                f = 1;
                break;
            }
            else
            {
                re--;
                if(re == 0)
                    break;
            }
        }
         st = k-temp.size();    
        }
    
    if(f==1 || st <0)
        w.println("-1");
    else
    {
           
        int div = 10000/k;
        int mod = 10000%k;
        Iterator itr = temp.iterator();
        while(itr.hasNext())
        {
            Integer e = (Integer) itr.next();
            a[st] = e;
            st++;
        }
        w.println("10000");
        for(int i=0;i<div;i++)
        {
            for(int j=0;j<k;j++)
            {
                w.print(a[j] + " ");
            }
        }
        for(int i=0;i<mod;i++)
        {
            w.print(a[i] + " ");
        }
        w.println();
    }
*/
     int n = sc.ni();
     int k = sc.ni();
     int []m = new int[k+1];
     int []c = new int[k+1];
     for(int i=0;i<n;i++)
     {
         m[sc.ni()]++;
     }
     for(int i=1;i<=k;i++)
     {
         c[i] = sc.ni();
         
     }
     
     long sum = 0;
     long size = 0;
     for(int i=k;i>=1;i--)
     {
         sum += (long) m[i];
         size = Math.max(size, (long) Math.ceil(sum / (double) c[i]));
         
     }
     ArrayList<ArrayList<Integer>> res = new ArrayList<>();
     for(int i=0;i<size;i++)
     {
         res.add(new ArrayList<>());
     }
     int pos = 0;
     for(int i=k;i>=1;i--)
     {
         for(int j=0;j<m[i];j++)
         {
             ArrayList<Integer> p = res.get(pos);
             p.add(i);
             res.add(p);
             pos = (pos+1)%(int)size;
         }
     }
     w.println(size);
     for(int i=0;i<size;i++)
     {
         w.print(res.get(i).size() + " ");
         for(int j=0;j<res.get(i).size();j++)
         {
             w.print(res.get(i).get(j) + " ");
         }
         w.println();
     }
     
 
       w.close();
       
        
    
    
} 
   
    static int []res;
    static int c = 0;
    static class Pair{
        int fir;
        int last;
        Pair(int fir,int last)
        {
            this.fir = fir;
            this.last = last;
        }
    }
    static class m1 implements Comparator<Pair>{
        public int compare(Pair a, Pair b)
        {
            int t1 = a.last - a.fir;
            int t2 = b.last - b.fir;
            if(t1 < t2)
                return 1;
            else if(t1 > t2)
                return -1;
            else
            {
                if(a.fir < b.fir)
                    return -1;
                else
                    return 1;
            }
        }
    }
   
    static long calc(long x)
    {
        double res = Math.sqrt(1 + 24*(double)x);
        res -= 1.0;
        res = res / (double) 6;
        return (long) res;
    }
   
 public static final BigInteger MOD = BigInteger.valueOf(998244353L);
    
    static BigInteger fact(int x)
    {
        BigInteger res = BigInteger.ONE;
        for(int i=2;i<=x;i++)
        {
            res = res.multiply(BigInteger.valueOf(i)).mod(MOD);
        }
        return res;
    }
   
    public static long calc(int x,int y,int z)
    {
        long res = ((long) (x-y) * (long) (x-y)) + ((long) (z-y) * (long) (z-y)) + ((long) (x-z) * (long) (x-z));
        return res;
    }
    
    public static int upperBound(ArrayList<Integer>arr, int length, int value) {
        int low = 0;
        int high = length;
        while (low < high) {
            final int mid = (low + high) / 2;
            if (value >= arr.get(mid)) {
                low = mid + 1;
            } else {
                high = mid;
            }
        }
        return low;
    }
    
     public static int lowerBound(ArrayList<Integer> arr, int length, int value) {
        int low = 0;
        int high = length;
        while (low < high) {
            final int mid = (low + high) / 2;
            //checks if the value is less than middle element of the array
            if (value <= arr.get(mid)) {
                high = mid;
            } else {
                low = mid + 1;
            }
        }
        return low;
    }
    static HashMap<Long,Integer> map;
  
          
    static class Coin{
        long a;
        long b;
        
        Coin(long a, long b)
        {
            this.a = a;
            this.b = b;
           
        }
    }
    static ArrayList<Long> fac;
    static HashSet<Long> hs;
    public static void primeFactors(long n) 
    { 
        // Print the number of 2s that divide n 
        while (n % 2 == 0) { 
            fac.add(2l);
            hs.add(2l);
            n /= 2; 
        } 
  
        // n must be odd at this point.  So we can 
        // skip one element (Note i = i +2) 
        for (long i = 3; i*i <= n; i += 2) { 
            // While i divides n, print i and divide n 
            while (n % i == 0) { 
                fac.add(i);
                hs.add(i);
                n /= i; 
            } 
        } 
  
        // This condition is to handle the case whien 
        // n is a prime number greater than 2 
        if (n > 2) 
            fac.add(n);
    } 
   static int smallestDivisor(int n)  
{  
    // if divisible by 2  
    if (n % 2 == 0)  
        return 2;  
  
    // iterate from 3 to sqrt(n)  
    for (int i = 3; i * i <= n; i += 2) {  
        if (n % i == 0)  
            return i;  
    }  
  
    return n;  
}  
 static boolean IsP(String s,int l,int r)
 {
      while(l <= r)
      {
          if(s.charAt(l) != s.charAt(r))
          {
              return false;
          }
         l++;
         r--;
      }
      return true;
 }
  
	

    
    
 static class Student{
    int id;
    int val;
     Student(int id,int val)
     {
      this.id = id;
      this.val = val;
     }
 }
   
   
   
 
     static int upperBound(ArrayList<Integer> a, int low, int high, int element){
    while(low < high){
        int middle = low + (high - low)/2;
        if(a.get(middle) >= element)
            high = middle;
        else 
            low = middle + 1;
    }
    return low;
}
   static long func(long t,long e,long h,long a, long b)
   {
       if(e*a >= t)
           return t/a;
       else
       {
           return e + Math.min(h,(t-e*a)/b);
       }
   }
         
      
   
    public static int countSetBits(int number){
        int count = 0;
        while(number>0){
            ++count;
            number &= number-1;
        }
        return count;
    }
    
     
      
 
    
   
     static long modexp(long x,long n,long M)
{
    long power = n;
    long result=1;
    x = x%M;
    while(power>0)
    {
        if(power % 2 ==1)
            result=(result * x)%M;
        x=(x*x)%M;
        power = power/2;
    }
    return result;
}
      static long modInverse(long A,long M)
{
    return modexp(A,M-2,M);
}
    static long gcd(long a,long b)
    {
        if(a==0)
            return b;
        else
            return gcd(b%a,a);
    }
    static class Temp{
        int a;
        int b;
        int c;
        int d;
      
        Temp(int a,int b,int c,int d)
        {
            this.a = a;
            this.b = b;
            this.c  =c;
            this.d = d;
            //this.d = d;
        }
    }
   
    
    
   static long sum1(int t1,int t2,int x,int []t)
   {
       int mid = (t2-t1+1)/2;
  if(t1==t2)
      return 0;
    
   else
   return sum1(t1,mid-1,x,t) + sum1(mid,t2,x,t);
    
     
   }
  
   
    static String replace(String s,int a,int n)
    {
        char []c = s.toCharArray();
        for(int i=1;i<n;i+=2)
        {
            int num = (int) (c[i] - 48);
            num += a;
            num%=10;
            c[i] = (char) (num+48);
        }
        return new String(c);
    }
    static String move(String s,int h,int n)
    {
        h%=n;
        char []c = s.toCharArray();
        char []temp = new char[n];
        for(int i=0;i<n;i++)
        {
            temp[(i+h)%n] = c[i];
        }
        return new String(temp);
    }
    
     public static int ip(String s){
return Integer.parseInt(s);
}
     static class multipliers implements Comparator<Long>{
  
         
  public int compare(Long a,Long b) {
   if(a<b)
    return 1;
   else if(b<a)
    return -1;
   else
    return 0;
  }
 }
     
     static class multipliers1 implements Comparator<Coin>{
  
  public int compare(Coin a,Coin b) {
   if(a.a < b.a)
       return 1;
   else if(a.a > b.a)
       return -1;
   else{ 
       if(a.b < b.b)
       return 1;
   else if(a.b > b.b)
       return -1;
       else
       return 0;
   }
       
  
 
     }
     }
     
// Java program to generate power set in 
// lexicographic order. 
 
    
    
    
      static class InputReader {
 
private final InputStream stream;
private final byte[] buf = new byte[8192];
private int curChar, snumChars;
 
public InputReader(InputStream st) {
this.stream = st;
}
 
public int read() {
if (snumChars == -1)
throw new InputMismatchException();
if (curChar >= snumChars) {
curChar = 0;
try {
snumChars = stream.read(buf);
} catch (IOException e) {
throw new InputMismatchException();
}
if (snumChars <= 0)
return -1;
}
return buf[curChar++];
}
 
public int ni() {
int c = read();
while (isSpaceChar(c)) {
c = read();
}
int sgn = 1;
if (c == '-') {
sgn = -1;
c = read();
}
int res = 0;
do {
res *= 10;
res += c - '0';
c = read();
} while (!isSpaceChar(c));
return res * sgn;
}
 
public long nl() {
int c = read();
while (isSpaceChar(c)) {
c = read();
}
int sgn = 1;
if (c == '-') {
sgn = -1;
c = read();
}
long res = 0;
do {
res *= 10;
res += c - '0';
c = read();
} while (!isSpaceChar(c));
return res * sgn;
}
 
public int[] nia(int n) {
int a[] = new int[n];
for (int i = 0; i < n; i++) {
a[i] = ni();
}
return a;
}
 
public String rs() {
int c = read();
while (isSpaceChar(c)) {
c = read();
}
StringBuilder res = new StringBuilder();
do {
res.appendCodePoint(c);
c = read();
} while (!isSpaceChar(c));
return res.toString();
}
 
public String nextLine() {
int c = read();
while (isSpaceChar(c))
c = read();
StringBuilder res = new StringBuilder();
do {
res.appendCodePoint(c);
c = read();
} while (!isEndOfLine(c));
return res.toString();
}
 
public boolean isSpaceChar(int c) {
return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
}
 
private boolean isEndOfLine(int c) {
return c == '\n' || c == '\r' || c == -1;
}
 
}
 
 
 
 
 
   
static PrintWriter w = new PrintWriter(System.out);
                  static class Student1
    {
        int id;
        //int x;
       
       int b;
      
        //long z;
        
        Student1(int id,int b)
        {
            this.id = id;
            //this.x = x;
            //this.s = s;
            this.b = b;
          
           // this.z = z;
            
            
            
           
        }
        
    }
}