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.
import java.util.*;



import java.io.*;
import java.math.BigDecimal;


 
 public class Main {
 
    public static void main(String[] args) {
         
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader inp = new InputReader(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        Solver solver = new Solver();
        solver.solve(inp, out);
        out.close();
 
    }
 
 
 
 
 
    static class Solver {
 
        class pair implements Comparable<pair>{
 
            int i;
            int cnt;
            public pair(int i,int cnt)
            {
                this.i=i;
                this.cnt=cnt;
            }
 
            public int compareTo(pair p)
            {
                return Long.compare(this.i,p.i);
            }
 
        }
 
        class Node implements Comparable < Node > {
            int i;
            int cnt;
 
            Node(int i, int cnt) {
                this.i = i;
                this.cnt = cnt;
            }
 
            public int compareTo(Node n) {
                if (this.cnt == n.cnt) {
                    return Integer.compare(this.i, n.i);
                }
                return Integer.compare(this.cnt, n.cnt);
            }
        }
 
        public boolean done(int[] sp, int[] par) {
            int root;
 
            root = findSet(sp[0], par);
 
            for (int i = 1; i < sp.length; i++) {
                if (root != findSet(sp[i], par))
                    return false;
            }
            return true;
        }
        public int findSet(int i, int[] par) {
            int x = i;
            boolean flag = false;
            while (par[i] >= 0) {
                flag = true;
                i = par[i];
            }
            if (flag)
                par[x] = i;
            return i;
        }
 
        public void unionSet(int i, int j, int[] par) {
            int x = findSet(i, par);
            int y = findSet(j, par);
            if (x < y) {
                par[y] = x;
            } else {
                par[x] = y;
            }
        }
 
        public long pow(long a, long b, long MOD) {
            if (b == 0) {
                return 1;
            }
            if (b == 1) {
                return a;
            }
            long val = pow(a, b / 2, MOD);
            if (b % 2 == 0) {
                return val * val % MOD;
            } else {
                return val * (val * a % MOD) % MOD;
 
            }
 
        }
 
        public boolean isPrime(int n)
        {
            for(int i=2;i<n;i++)
            {
                if(n%i==0)
                {
                    return false;
                }
            }
            return true;
        }
 
 
        public void minPrimeFactor(int n, int[] s) {
            boolean prime[] = new boolean[n + 1];
            Arrays.fill(prime, true);
            s[1] = 1;
            s[2] = 2;
            for (int i = 4; i <= n; i += 2) {
                prime[i] = false;
                s[i] = 2;
            }
 
            for (int i = 3; i <= n; i += 2) {
                if (prime[i]) {
                    s[i] = i;
                    for (int j = 2 * i; j <= n; j += i) {
                        prime[j] = false;
                        s[j] = i;
                    }
                }
            }
 
        }
 
 
        public void findAllPrime(int n, ArrayList < Node > al, int s[]) {
            int curr = s[n];
            int cnt = 1;
            while (n > 1) {
                n /= s[n];
                if (curr == s[n]) {
                    cnt++;
                    continue;
 
                }
                Node n1 = new Node(curr, cnt);
                al.add(n1);
 
                curr = s[n];
                cnt = 1;
            }
        }
 
 
 
        public int binarySearch(int n, int k) {
            int left = 1;
            int right = 100000000 + 5;
            int ans = 0;
            while (left <= right) {
                int mid = (left + right) / 2;
                if (n / mid >= k) {
                    left = mid + 1;
                    ans = mid;
                } else {
                    right = mid - 1;
                }
            }
 
            return ans;
        }
        public boolean checkPallindrom(String s) {
            char ch[] = s.toCharArray();
 
            for (int i = 0; i < s.length() / 2; i++) {
                if (ch[i] != ch[s.length() - 1 - i])
                    return false;
            }
            return true;
        }

        public boolean pallindrom(String s1, String s2)
        {
            char ch[] = s1.toCharArray();
            char ch1[] = s2.toCharArray();

            for(int i=0;i<s1.length();i++)
            {
                if(ch[i]!=ch1[s1.length()-1-i])
                {
                    return false;
                }
            }

            return true;
        }
 
 
 
 
        public void remove(ArrayList < Integer > [] al, int x) {
            for (int i = 0; i < al.length; i++) {
                for (int j = 0; j < al[i].size(); j++) {
 
                    if (al[i].get(j) == x)
                        al[i].remove(j);
 
                }
            }
        }
 
        public long gcd(long a, long b) {
            if (a == 0)
                return b;
            return gcd(b % a, a);
        }
 
 
        public void printDivisors(long n, ArrayList < Long > al) {
            // Note that this loop runs till square root 
            for (long i = 1; i*i <= (n); i++) {
                if (n % i == 0) {
                    // If divisors are equal, print only one 
                    if (n / i == i) {
                        al.add(i);
                    } else // Otherwise print both 
                    {
                        al.add(i);
                        al.add(n / i);
                    }
 
                }
            }
        }
 
        public static long constructSegment(long seg[], long arr[], int low, int high, int pos) {
            if (low == high) {
                seg[pos] = arr[low];
                return seg[pos];
            }
            int mid = (low + high) / 2;
            long t1 = constructSegment(seg, arr, low, mid, (2 * pos) + 1);
            long t2 = constructSegment(seg, arr, mid + 1, high, (2 * pos) + 2);
            seg[pos] = t1 + t2;
            return seg[pos];
 
        }
        public static long querySegment(long seg[], int low, int high, int qlow, int qhigh, int pos) {
 
            if (qlow <= low && qhigh >= high) {
                return seg[pos];
            } else if (qlow > high || qhigh < low) {
                return 0;
            } else {
                long ans = 0;
                int mid = (low + high) / 2;
                ans += querySegment(seg, low, mid, qlow, qhigh, (2 * pos) + 1);
                ans += querySegment(seg, mid + 1, high, qlow, qhigh, (2 * pos) + 2);
                return ans;
            }
 
        }
        public static int lcs(char[] X, char[] Y, int m, int n) {
            if (m == 0 || n == 0)
                return 0;
            if (X[m - 1] == Y[n - 1])
                return 1 + lcs(X, Y, m - 1, n - 1);
            else
                return Integer.max(lcs(X, Y, m, n - 1), lcs(X, Y, m - 1, n));
        }
 
        public static long recursion(long start, long end, long cnt[], int a, int b) {
 
            long min = 0;
            long count = 0;
            int ans1 = -1;
            int ans2 = -1;
            int l = 0;
            int r = cnt.length - 1;
            while (l <= r) {
                int mid = (l + r) / 2;
                if (cnt[mid] >= start) {
                    ans1 = mid;
                    r = mid - 1;
                } else {
                    l = mid + 1;
                }
            }
 
            l = 0;
            r = cnt.length - 1;
            while (l <= r) {
                int mid = (l + r) / 2;
                if (cnt[mid] <= end) {
                    ans2 = mid;
                    l = mid + 1;
                } else {
                    r = mid - 1;
                }
            }
 
            if (ans1 == -1 || ans2 == -1 || ans2 < ans1) {
                // System.out.println("min1 "+min);
                min = a;
                return a;
 
            } else {
                min = b * (end - start + 1) * (ans2 - ans1 + 1);
            }
            if (start == end) {
                // System.out.println("min "+min);
                return min;
            }
            long mid = (end + start) / 2;
            min = Long.min(min, recursion(start, mid, cnt, a, b) + recursion(mid + 1, end, cnt, a, b));
            // System.out.println("min "+min);
            return min;
        }
 
 
        public int lowerBound(ArrayList<Long> al,long ele)
        {
            int l =0;
            int r =al.size()-1;
            int ans=-1;
            while(l<=r)
            {
                int mid = (l+r)/2;
                if(al.get(mid)<=ele)
                {
                    ans=mid;
                    l=mid+1;
                }
                else
                {
                    r=mid-1;
                }


            }
            return ans;
        }
        
        public int lowerBound(long arr[],long ele)
        {
            int l =0;
            int r =arr.length-1;
            int ans=-1;
            while(l<=r)
            {
                int mid = (l+r)/2;
                if(arr[mid]<=ele)
                {
                    ans=mid;
                    l=mid+1;
                }
                else
                {
                    r=mid-1;
                }


            }
            return ans;
        }
 
        public long dfs_util(ArrayList < Integer > [] al, boolean vis[], int x ,long arr[],long val) {
 
            vis[x] = true;

           
            long temp=0;
            for (int i = 0; i < al[x].size(); i++) {
 
                if (!vis[al[x].get(i)]) {
                    
                    temp+=dfs_util(al, vis, al[x].get(i),arr,val+1);
                }

            }
            arr[x]=val-(temp);
            return (temp+1);
           
          
        }
 
        public  long[] dfs(ArrayList[] al) {
            long arr[] = new long[al.length];
            boolean vis[] = new boolean[al.length];
            for (int i = 0; i < al.length; i++) {
                if (!vis[i]) {
                     dfs_util(al, vis, i,arr,0);
                }
            }
            return arr;
           
        }
 

        public void permute(String s,int l, int r,ArrayList<String> al)
        {
            if(l==r)
            {
                al.add(s);
                
            }
            for(int i=l;i<=r;i++)
            {
                String str=swap(s,l,i);
                permute(str, l+1, r, al);
                
            }
        
        }

        public String swap(String s, int l, int r)
        {
            char ch[] = s.toCharArray();
            char tem = ch[l];
            ch[l]=ch[r];
            ch[r]=tem;
            return String.valueOf(ch);
        }
        

        public int[] computeLps(String s)
        {
            int ans[] =new int[s.length()];
            char ch[] = s.toCharArray();
            int n = s.length();
            int i=1;
            int len=0;
            ans[0]=0;
            while(i<n)
            {
                if(ch[i]==ch[len])
                {
                    len++;
                    ans[i]=len;
                    i++;
                }
                else
                {
                    if(len!=0)
                    {
                        len=ans[len-1];
                    }
                    else
                    {
                        ans[i]=len;
                        i++;
                    }
                }
            }
 
            return ans;
 
        }

        public int longestPrefixSuffix(String s)  
        { 
            int n = s.length(); 
        
            if(n < 2) { 
                return 0; 
            } 
    
            int len = 0; 
            int i = n/2; 
            while(i < n) { 
                if(s.charAt(i) == s.charAt(len)) { 
                ++len; 
                ++i; 
            }  
            else 
            { 
            if(len == 0) { 
                ++i; 
            }  
            else 
            {  
                
                --len; 
            } 
            } 
    } 
        
    return len; 
          
} 

        public boolean convertFromBaseToBase(long num, int fromBase, int toBase,HashSet<Integer> hs) {
            StringBuilder s=new StringBuilder();
            boolean f=true;
            int cnt=0;
            while(num>0)
            {
               long tem = num%toBase;
               if(tem==1)
               {
                 if(hs.contains(cnt))
                 {
                     f=false;
                     break;
                 }
                 else
                 {
                     hs.add(cnt);
                 }
               }
               else if(tem==0)
               {

               }
               else
               {
                f=false;
                break;
               }
               num/=toBase;
               cnt++;

            }


            return f;
            
        }

        private boolean possible(long arr[],long d,long k)
        {
            long tem=0;
            for(int i=0;i<arr.length-1;i++)
            {
                tem+=(arr[i+1]-arr[i])/(d);

                if((arr[i+1]-arr[i])%d==0)
                    tem--;
                
            }
            if(tem<=k)
            {
                return true;
            }
            else
                return false;
            
        }

        public void bfsUtil(ArrayList<Integer> a[],int out[])
        {
            boolean vis[] = new boolean[a.length];
            for(int i=0;i<a.length;i++)
            {
                if(!vis[i])
                {
                    bipartie(a, vis,out,i);
                }
            }
        }


        public int[] bipartie(ArrayList<Integer> arr[],boolean vis[],int color[],int e)
        {
          
          
            Queue<Integer> q = new LinkedList<>();
            color[e]=1;
            q.add(e);
            while(!q.isEmpty())
            {
                int x = q.remove();
                if(vis[x])
                {
                    continue;
                }
                vis[x]=true;
                for(int i=0;i<arr[x].size();i++)
                {
                    if(!vis[arr[x].get(i)])
                    {
                        
                    }
                    else
                    {
                        if(color[arr[x].get(i)]==color[x])
                        {
                            color[x]=2;
                        }
                    }
                }

                for(int i=0;i<arr[x].size();i++)
                {
                    if(!vis[arr[x].get(i)])
                    {
                        if(color[x]==2)
                        {
                            color[arr[x].get(i)]=0;
                            
                        }
                        else
                        {
                            color[arr[x].get(i)]=1-color[x];
                            
                        }
                        q.add(arr[x].get(i));
                    }
                    
                }
            }
            return color;
        }

        
        
 
       public int dfs1(ArrayList<Integer> al[],int x,boolean arr[],int val,boolean vis[],long ans[])
       {
           vis[x]=true;
           if(arr[x])
           {
           

               ans[0]+=(long)val;
           }
           for (int i = 0; i < al[x].size(); i++) {
 
            if (!vis[al[x].get(i)]) {
                int temp = val;
                if(!arr[x])
                    temp++;
                dfs1(al, al[x].get(i),arr,temp,vis,ans);
            }

        }
            return 0;
       }
 
        private void solve(InputReader inp, PrintWriter out1) {

            int n = inp.nextInt();
            int k = inp.nextInt();
            Integer arr[] = new Integer[n];
            int cnt[] = new int[k+1];
            int c[] = new int[k];
            for(int i=0;i<n;i++)
            {
                arr[i] = inp.nextInt();
                cnt[arr[i]]++;
            }
            for(int i=k-1;i>=1;i--)
            {
                cnt[i]+=cnt[i+1];
            }

            for(int i=0;i<k;i++)
            {
                c[i] =inp.nextInt();
            }

            int ans=0;

            for(int i=0;i<k;i++)
            {
                ans = Math.max(ans, (int)Math.ceil(((double)cnt[i+1])/((double)c[i])));
            }
            ArrayList<Integer> al[] = new ArrayList[ans];

            for(int i=0;i<ans;i++)
            {
                al[i] = new ArrayList<Integer>();
            }
            Arrays.sort(arr);
            for(int i=0;i<n;i++)
            {
                al[i%ans].add(arr[i]);
            }

            out1.println(ans);
            for(int i=0;i<ans;i++)
            {
                out1.print(al[i].size()+" ");
                for(int j=0;j<al[i].size();j++)
                {
                    out1.print(al[i].get(j)+" ");
                }
             out1.println();
            }

        }

     
    }

 
 
    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;
 
        InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }
 
        String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }
 
        public int nextInt() {
            return Integer.parseInt(next());
        }
 
        public long nextLong() {
            return Long.parseLong(next());
        }
    }
}
class ele implements Comparable<ele>{
    int i;
    int dis;
    boolean mark;
    boolean leaf;
    public ele(int i,int dis)
    {
        this.i=i;
        this.dis=dis;
        this.mark=false;
        this.leaf=false;
    }
    @Override
    public int compareTo(ele e)
    {
       if(this.dis==e.dis)
       {
           if(e.leaf==true)
            return 1;
           else if(this.leaf)
            return -1;
           else
            return 0; 
       }
        
        return -Integer.compare(this.dis,e.dis);
    }
}