In a strategic computer game "Settlers II" one has to build defense structures to expand and protect the territory. Let's take one of these buildings. At the moment the defense structure accommodates exactly n soldiers. Within this task we can assume that the number of soldiers in the defense structure won't either increase or decrease.

Every soldier has a rank — some natural number from 1 to k. 1 stands for a private and k stands for a general. The higher the rank of the soldier is, the better he fights. Therefore, the player profits from having the soldiers of the highest possible rank.

To increase the ranks of soldiers they need to train. But the soldiers won't train for free, and each training session requires one golden coin. On each training session all the n soldiers are present.

At the end of each training session the soldiers' ranks increase as follows. First all the soldiers are divided into groups with the same rank, so that the least possible number of groups is formed. Then, within each of the groups where the soldiers below the rank k are present, exactly one soldier increases his rank by one.

You know the ranks of all n soldiers at the moment. Determine the number of golden coins that are needed to increase the ranks of all the soldiers to the rank k.

Input

The first line contains two integers n and k (1 ≤ n, k ≤ 100). They represent the number of soldiers and the number of different ranks correspondingly. The second line contains n numbers in the non-decreasing order. The i-th of them, ai, represents the rank of the i-th soldier in the defense building (1 ≤ i ≤ n, 1 ≤ ai ≤ k).

Output

Print a single integer — the number of golden coins needed to raise all the soldiers to the maximal rank.

Examples

Input

4 4
1 2 2 3


Output

4

Input

4 3
1 1 1 1


Output

5

Note

In the first example the ranks will be raised in the following manner:

1 2 2 3 →  2 2 3 4 →  2 3 4 4 →  3 4 4 4 →  4 4 4 4

Thus totals to 4 training sessions that require 4 golden coins.
import java.io.*;
import java.util.*;
import java.util.Queue;
import java.util.LinkedList;
import java.util.Stack;
import java.math.*;
public class Fast
{
    @SuppressWarnings("unchecked")
    static long s[],a[],k=0,sum=0;
    static Vector adj[];static int x=0;
     public static void main(String args[])throws IOException
    {
        Reader ob=new Reader();
        Writer out=new Writer(System.out);
        int n=ob.nI(),k=ob.nI();
        int a[]=new int[101],ans=0;
        for(int i=0;i<n;i++)
        a[ob.nI()]++;
        while(a[k]!=n)
        {
            ans++;
            int b[]=new int[101];
            for(int i=1;i<=100;i++)
            b[i]=a[i];
            for(int i=1;i<k;i++)
            {
                if(a[i]!=0)
                {
                    b[i]--;
                    b[i+1]++;
                }
            }
            for(int i=1;i<=100;i++)
            a[i]=b[i];
            
            
            
        }
        out.pln(ans);
    out.flush();
}
static void dfsum(int n)
{
    int l=adj[n].size();
    long su=a[n];
    for(int i=0;i<l;i++)
    {
        
        int r=(int)adj[n].get(i);
        dfsum(r);
        su+=s[r];
    }
    s[n]=su;
    
}
static void dfs(int n)
{
    int l=adj[n].size();
    if(!(s[n]<0&&s[n]+x<0&&a[n]<0))
    {
    for(int i=0;i<l;i++)
    {
        int r=(int)adj[n].get(i);
        dfs(r);
    }
}
    else
{
    sum=sum-s[n]-x;
    
}
}
static void bfs(int ss)
{
    
        Queue q=new Queue();
        q.add(ss);
        while(!q.isEmpty())
        {
            int r=q.remove();
            if(s[r]>0)
            {
            int l=adj[r].size();
            for(int i=0;i<l;i++)
            {
                int y=(int)adj[r].get(i);
                
            }
        }
        else
        {
            k++;
            sum-=s[r];
        }
    }
        
        
        
    
    
}
public static void bfs(int s, ArrayList<Integer> adj[],boolean vis[],int n)
    {
        //Add your code here.
        Queue q=new Queue();
        q.add(s);
        vis[s]=true;
        while(!q.isEmpty())
        {
            int r=q.remove();
            int l=adj[r].size();
            for(int i=0;i<l;i++)
            {
                int y=adj[r].get(i);
                if(!vis[y])
                {
                    q.add(y);
                    vis[y]=true;

                }
               
            }
        }
    }
static void debug(Object... o) {
        System.err.println(Arrays.deepToString(o));
    }
static long inverse(long x, long p)
    {
        return pow(x, p - 2, p);
    }
static boolean isPrime(long n)
{
    long h=(long)Math.sqrt(n);
    for(long i=2;i<=h;i++)
    if(n%i==0)
    return false;
    return true&&n!=1;
}
    static long gcd(long a,long b)
    {
        if(a<b)
        return gcd(b,a);
        else if(b==0)
        return a;
        else
        return gcd(b,a%b);
    }
    static long pow(long a,long b,long mod){
		if(b == 0)	return 1;
		long t = pow(a,b>>1,mod);
		t = (t * t) % mod;
		if((b & 1) == 1)	t = (t * a);
		if(t >= mod)	t %= mod;
		return t;
}
    static long pow(long a,long b){
		if(b == 0)	return 1;
		long t = pow(a,b>>1);
		t = (t * t);
		if((b & 1) == 1)	t = (t * a);
		return t;
}
    static void seive(int n,int prime[])//1 for prime -1 for not prime
    {
        for(int i=2;i<=n;i++)
            if(prime[i]==0)
            {
                prime[i]=1;
                for(int j=2;j*i<=n;j++)
                prime[j*i]=-1;
            }
    }
    static int max(int ...a)
    {
        int m=a[0];
        for(int i=0;i<a.length;i++)
        m=Math.max(m,a[i]);
        return m;
        
    }
    static long max(long ...a)
    {
        long m=a[0];
        for(int i=0;i<a.length;i++)
        m=Math.max(m,a[i]);
        return m;
    }
    static int min(int ...a)
    {
        int m=a[0];
        for(int i=0;i<a.length;i++)
        m=Math.min(m,a[i]);
        return m;
    }
    static long min(long ...a)
    {
        long m=a[0];
        for(int i=0;i<a.length;i++)
        m=Math.min(m,a[i]);
        return m;
    }
    static class Pair
    {
        int x=0,y=0;
        Pair(int xx,int yy)
        {
            x=xx;
            y=yy;
        }
    }
    static class Queue
{
    Node head,tail;
    void add(int n)
    {
       Node tmp=new Node(n);
       if(head==null)
       {
           head=tmp;
           tail=tmp;
        }
        else
        {
            tail.next=tmp;
            tail=tmp;
        }
    }
    int remove()
   {
       if(head!=null)
       {
           int d=head.data;
           head=head.next;
           return d;
        }
        return -1;
    }
    int peek()
    {
        if(head!=null)
        return head.data;
        return -1;
    }
    void display()
    {
        Node tmp=head;
        while(tmp!=null)
        {
            System.out.print(tmp.data+" ");
            tmp=tmp.next;
        }
        System.out.println();
    }
    boolean isEmpty()
    {
        return head==null;
    }
}
static class Node 
{
    int data;
    Node next;
    Node(int n)
    {
       data=n;
    }
}
	static class Writer {
		private final PrintWriter p;
		Writer(OutputStream o) {
			p = new PrintWriter(new BufferedWriter(new OutputStreamWriter(o)));
		}
		void p(Object... o1) {
			for (Object o11 : o1) {
				p.print(o11 + "" );
			}
		}
		void p(String s) {
			p.print(s);
		}
		void pln(Object... o1) {
			p(o1);
			p.println();
		}
		void flush() {
			p.flush();
		}
		void close() {
			p.close();
		}
	}
    static class Reader {
		private byte[] buf = new byte[1024];
		private int curChar;
		private int snumChars;
		public int read() {
			if (snumChars == -1)
				throw new InputMismatchException();
			if (curChar >= snumChars) {
				curChar = 0;
				try {
					snumChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (snumChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}
		public String nl() {
			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 String n() {
			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 long nL() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
		public int nI() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}
		public int[] NIA(int n) //nextINtArray
		{
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nI();
			}
			return arr;
		}
		public int[] NIA1(int n) //nextINtArray
		{
			int[] arr = new int[n+1];
			for (int i = 1; i <=n; i++) {
				arr[i] = nI();
			}
			return arr;
		}
		
		public long[] NLA(int n) //nextLongArray
		{
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nL();
			}
			return arr;
}
		public long[] NLA1(int n) //nextLongArray
		{
			long[] arr = new long[n+1];
			for (int i = 1; i <=n; i++) {
				arr[i] = nL();
			}
			return arr;
}
		private 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 class DisJoint
{
    int a[],rank[];
    DisJoint(int n)
    {
        a=new int[n+1];
        rank=new int[n+1];
        for(int i=1;i<=n;i++)
    {
        a[i]=i;
        rank[i]=1;
    }
    }
    int find(int n)
    {
        if(a[n]==n)
        return n;
        else
        return find(a[n]);
    }
    void union(int a1,int b)
    {
        int x=find(a1);
        int y=find(b);
        if(rank[x]>rank[y])
    {
        a[y]=x;
        rank[x]+=1;
    }
    else
    {
       a[x]=y;
       rank[y]+=1;
    }
        //System.out.println(Arrays.toString(a));
    }
}
class Segment
{
    int sum[];
    void build(int a[],int v,int l,int r)
    {
        if(l==r)
        sum[v]=a[l];
        else
        {
            int m=(l+r)/2;
            build(a,v*2,l,m);
            build(a,2*v+1,m+1,r);
            sum[v]=sum[v*2]+sum[2*v+1];
        }
    }
    void update(int a[],int l,int r,int x,int v,int y)
    {
        if(l==r&&r==y)
            sum[v]+=x;
        else if(l>y||y>r)
        return;
        else
        {
            int m=(l+r)/2;
            update(a,l,m,x,2*v,y);
            update(a,m+1,r,x,2*v+1,y);
            sum[v]=sum[2*v]+sum[2*v+1];
        }
    }
    int query(int v,int l,int r,int x,int y)
    {
        if(x>r||y<l)
        return 0;
        else if(x<=l&&r<=y)
        return sum[v];
        else
        {
            int m=(l+r)/2;
        return query(2*v,l,m,x,y)+query(2*v+1,m+1,r,x,y);  
    }
}
}

static class Trie
  {
      Trie child[]=new Trie[26];
      int count=0;
    }
   /* void insert(String a)
    {
        Trie tmp=root;
        for(int i=0;i<a.length();i++)
        {
            int v=a.charAt(i)-'a';
            if(tmp.child[v]==null)
            {
                tmp.child[v]=new Trie();
                
            }
                tmp=tmp.child[v];
            }
            if(tmp.count==0)
            r++;
            tmp.count=1;
        }*/
    }