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.
// Don't place your source in a package
import java.util.*;
import java.lang.*;
import java.io.*;
import java.math.*; 
 
 /*
 
 6666666666666			 6666666666666                     
 6						 6  											   			
 6						 6                                      
 6						 6                                      
 6						 6                                       
 6                       6                                                 
 6666666666666           6666666666666                     
 6		     6           6		     6
 6			 6	         6			 6 
 6			 6           6			 6
 6		     6	         6		     6	
 6666666666666           6666666666666
 
 
 */
 
 
 
 
 
// Please name your class Main
public class Main {
	
	//static StreamTokenizer in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
 
    /*static int read() throws IOException {
        in.nextToken();
        return (int) in.nval;
    }
    static String readString() throws IOException {
        in.nextToken();
        return in.sval;
	}*/
	
	
	static Scanner in = new Scanner(System.in);
	
	public static void main (String[] args) throws java.lang.Exception {
	    
		//InputReader in = new InputReader(System.in);
		PrintWriter out = new PrintWriter(System.out);
		
 
		int T=1;
		
		for(int t=0;t<T;t++){
			int n=Int();int k=Int();
			int A[]=new int[n];
			for(int i=0;i<n;i++){
				A[i]=Int();
			}
			
			Solution sol=new Solution();
			sol.solution(A,k);
		}
 
		out.flush();
	}
 
	public static int Int(){
		return in.nextInt();
	}
	public static String Str(){
		return in.next();
	}
}
 
class Solution{
	//constant variable
	final int MAX=Integer.MAX_VALUE;
	final int MIN=Integer.MIN_VALUE;
	//Set<Integer>adjecent[];
	//////////////////////////////
 
	
	
	public void solution(int A[],int k){
		int res=0;
		Arrays.sort(A);
		while(A[0]!=k){
			res++;
			for(int i=0;i<A.length;i++){
				int j=i;
				while(j<A.length&&A[j]==A[i]){
					j++;
				}
				A[i]++;
				i=j-1;
			}
			Arrays.sort(A);
		}
		msg(res+"");
	}

	

 
 
	
	
 
 
	
	
		
	
	public void swap(int A[],int l,int r){
		int t=A[l];
		A[l]=A[r];
		A[r]=t;
	}
	
 
	
	
	public long C(long fact[],int i,int j){ // C(20,3)=20!/(17!*3!)
		// take   a/b     where a=20!  b=17!*3!
		if(j>i)return 0;
		if(j==0)return 1;
		long mod=1000000007;
		long a=fact[i];
		long b=((fact[i-j]%mod)*(fact[j]%mod))%mod;
		BigInteger B= BigInteger.valueOf(b);
		long binverse=B.modInverse(BigInteger.valueOf(mod)).longValue();
		return ((a)*(binverse%mod))%mod;
	}
	
	
	 
	
	//map operation
	public void put(Map<Integer,Integer>map,int i){
		if(!map.containsKey(i))map.put(i,0);
		map.put(i,map.get(i)+1);
	}
	
	public void delete(Map<Integer,Integer>map,int i){
		map.put(i,map.get(i)-1);
		if(map.get(i)==0)map.remove(i);
	}
 
 
 
 
 
	
 
 
	/*public void tarjan(int p,int r){
		if(cut)return;
		List<Integer>childs=adjecent[r];
		dis[r]=low[r]=time;
		time++;
		
		//core for tarjan
		int son=0;
		for(int c:childs){
			if(ban==c||c==p)continue;
			if(dis[c]==-1){
				son++;
				tarjan(r,c);
				low[r]=Math.min(low[r],low[c]);
				if((r==root&&son>1)||(low[c]>=dis[r]&&r!=root)){
					cut=true;
					return;
				}
			}else{
				if(c!=p){
					low[r]=Math.min(low[r],dis[c]);
				}
			}
		}
		
	}*/
	
	
 
	
	//helper function I would use
	public void remove(Map<Integer,Integer>map,int i){
		map.put(i,map.get(i)-1);
		if(map.get(i)==0)map.remove(i);
	}
	
	
	
	public void ascii(String s){
		for(char c:s.toCharArray()){
			System.out.print((c-'a')+" ");
		}
		msg("");
	}
	
	public int flip(int i){
		if(i==0)return 1;
		else return 0;
	}
	
	public boolean[] primes(int n){
		boolean A[]=new boolean[n+1];
		for(int i=2;i<=n;i++){
			if(A[i]==false){
				for(int j=i+i;j<=n;j+=i){
					A[j]=true;
				}
			}
		}
		return A;
	}
	
	public void msg(String s){
		System.out.println(s);
	}
	
	public void msg1(String s){
		System.out.print(s);
	}
	
	public int[] kmpPre(String p){
		int pre[]=new int[p.length()];
		int l=0,r=1;
		while(r<p.length()){
			if(p.charAt(l)==p.charAt(r)){
				pre[r]=l+1;
				l++;r++;
			}else{
				if(l==0)r++;
				else l=pre[l-1];
			}
		}
		return pre;
	}
	
	public boolean isP(String s){
		int l=0,r=s.length()-1;
		while(l<r){
			if(s.charAt(l)!=s.charAt(r))return false;
			l++;r--;
		}
		return true;
	}
	
	public int find(int nums[],int x){//union find => find method
		if(nums[x]==x)return x;
		int root=find(nums,nums[x]);
		nums[x]=root;
		return root;
	}
	
 
	
	public int get(int A[],int i){
		if(i<0||i>=A.length)return 0;
		return A[i];
	}
	public int[] copy1(int A[]){
		int a[]=new int[A.length];
		for(int i=0;i<a.length;i++)a[i]=A[i];
		return a;
	}
	
	
	public void print1(long A[]){
		for(long i:A)System.out.print(i+" ");
		System.out.println();
	}
	public void print2(int A[][]){
		for(int i=0;i<A.length;i++){
			for(int j=0;j<A[0].length;j++){
				System.out.print(A[i][j]+" ");
			}System.out.println();
		}
	}
	
	public int min(int a,int b){
		return Math.min(a,b);
	}
	
	
	public int[][] matrixdp(int[][] grid) {
        if(grid.length==0)return new int[][]{};
        int res[][]=new int[grid.length][grid[0].length];
        for(int i=0;i<grid.length;i++){
            for(int j=0;j<grid[0].length;j++){
                res[i][j]=grid[i][j]+get(res,i-1,j)+get(res,i,j-1)-get(res,i-1,j-1);
            }
        }
        return res;
    }
    
    public int get(int grid[][],int i,int j){
        if(i<0||j<0||i>=grid.length||j>=grid[0].length)return 0;
        return grid[i][j];
    }
	
	public int[] suffixArray(String s){
		int n=s.length();
		Suffix A[]=new Suffix[n];
		
		for(int i=0;i<n;i++){
			A[i]=new Suffix(i,s.charAt(i)-'a',0);
		}
		
		for(int i=0;i<n;i++){
			if(i==n-1){
				A[i].next=-1;
			}else{
				A[i].next=A[i+1].rank;
			}
		}
		Arrays.sort(A);
		
		for(int len=4;len<A.length*2;len<<=1){
			int in[]=new int[A.length];
			int rank=0;
			int pre=A[0].rank;
			A[0].rank=rank;
			in[A[0].index]=0;
			for(int i=1;i<A.length;i++){//rank for the first two letter
				if(A[i].rank==pre&&A[i].next==A[i-1].next){
					pre=A[i].rank;
					A[i].rank=rank;
				}else{
					pre=A[i].rank;
					A[i].rank=++rank;
				}
				in[A[i].index]=i;
			}
			
			for(int i=0;i<A.length;i++){
				int next=A[i].index+len/2;
				if(next>=A.length){
					A[i].next=-1;
				}else{
					A[i].next=A[in[next]].rank;
				}
			}
			
			
			Arrays.sort(A);
		}
		
		
		int su[]=new int[A.length];
		for(int i=0;i<su.length;i++){
			su[i]=A[i].index;
		}
		return su;
	}
	
}
 
//suffix array Struct
class Suffix implements Comparable<Suffix>{
	int index;
	int rank;
	int next;
	public Suffix(int i,int rank,int next){
		this.index=i;
		this.rank=rank;
		this.next=next;
	}
	
	@Override
	public int compareTo(Suffix other) {
		if(this.rank==other.rank){
			return this.next-other.next;
		}
		return this.rank-other.rank;
	}
	
	public String toString(){
		return this.index+"   "+this.rank+"   "+this.next+"  ";
	}
}
 
 
 
class Wrapper implements Comparable<Wrapper>{
	int spf;int cnt;
	public Wrapper(int spf,int cnt){
		this.spf=spf;
		this.cnt=cnt;
	}
		
	@Override
	public int compareTo(Wrapper other) {
		return this.spf-other.spf;
	}
}
 
 
 
    class Node{//what the range would be for that particular node
		boolean state=false;
        int l=0,r=0;
		int ll=0,rr=0;
        public Node(boolean state){
            this.state=state;
        }
    }
	
	
	
	
	class Seg1{
			int A[];
			public Seg1(int A[]){
				this.A=A;
			}
			
			public void update(int left,int right,int val,int s,int e,int id){
				if(left<0||right<0||left>right)return;
				if(left==s&&right==e){
					
					A[id]+=val;
					return;
				}
				int mid=s+(e-s)/2; //[s,mid] [mid+1,e]
				
				if(left>=mid+1){
					update(left,right,val,mid+1,e,id*2+2);
				}else if(right<=mid){
					update(left,right,val,s,mid,id*2+1);
				}else{
					update(left,mid,val,s,mid,id*2+1);
					update(mid+1,right,val,mid+1,e,id*2+2);
				}
			}
			
			public int query(int i,int add,int s,int e,int id){
				
				if(s==e&&i==s){
					return A[id]+add;
				}
				
				int mid=s+(e-s)/2; //[s,mid] [mid+1,e]
				
				if(i>=mid+1){
					return query(i,A[id]+add,mid+1,e,id*2+2);
				}else{
					return query(i,A[id]+add,s,mid,id*2+1);
				}
			}
	}
 
 
	 class MaxFlow{
		
 
		  public static List<Edge>[] createGraph(int nodes) {
			List<Edge>[] graph = new List[nodes];
			for (int i = 0; i < nodes; i++)
			  graph[i] = new ArrayList<>();
			return graph;
		  }
 
		  public static void addEdge(List<Edge>[] graph, int s, int t, int cap) {
			graph[s].add(new Edge(t, graph[t].size(), cap));
			graph[t].add(new Edge(s, graph[s].size() - 1, 0));
		  }
 
		  static boolean dinicBfs(List<Edge>[] graph, int src, int dest, int[] dist) {
			Arrays.fill(dist, -1);
			dist[src] = 0;
			int[] Q = new int[graph.length];
			int sizeQ = 0;
			Q[sizeQ++] = src;
			for (int i = 0; i < sizeQ; i++) {
			  int u = Q[i];
			  for (Edge e : graph[u]) {
				if (dist[e.t] < 0 && e.f < e.cap) {
				  dist[e.t] = dist[u] + 1;
				  Q[sizeQ++] = e.t;
				}
			  }
			}
			return dist[dest] >= 0;
		  }
 
		  static int dinicDfs(List<Edge>[] graph, int[] ptr, int[] dist, int dest, int u, int f) {
			if (u == dest)
			  return f;
			for (; ptr[u] < graph[u].size(); ++ptr[u]) {
			  Edge e = graph[u].get(ptr[u]);
			  if (dist[e.t] == dist[u] + 1 && e.f < e.cap) {
				int df = dinicDfs(graph, ptr, dist, dest, e.t, Math.min(f, e.cap - e.f));
				if (df > 0) {
				  e.f += df;
				  graph[e.t].get(e.rev).f -= df;
				  return df;
				}
			  }
			}
			return 0;
		  }
 
		  public static int maxFlow(List<Edge>[] graph, int src, int dest) {
			int flow = 0;
			int[] dist = new int[graph.length];
			while (dinicBfs(graph, src, dest, dist)) {
			  int[] ptr = new int[graph.length];
			  while (true) {
				int df = dinicDfs(graph, ptr, dist, dest, src, Integer.MAX_VALUE);
				if (df == 0)
				  break;
				flow += df;
			  }
			}
			return flow;
		  }
		 
	 }
	 
	 	 class Edge {
			int t, rev, cap, f;
 
			public Edge(int t, int rev, int cap) {
			  this.t = t;
			  this.rev = rev;
			  this.cap = cap;
			}
		  }
		  
		  
		  
		  
		  
		  
    class Seg{
        int l,r;
        int min=Integer.MAX_VALUE;
        Seg left=null,right=null;
		long sum=0;long cnt=0;
        public Seg(int l,int r){
            this.l=l;
            this.r=r;
            
        }
        public long[] query(int s,int e){
            if(l==s&&r==e){
                return new long[]{sum,cnt};
            }
            int mid=l+(r-l)/2; //left :  to mid-1,
			
			if(left==null)left=new Seg(l,mid);
			if(right==null)right=new Seg(mid+1,r);
            
			if(e<=mid){
                return left.query(s,e);
            }
            else if(s>=mid+1){
                return right.query(s,e);
            }else{
				long A[]=left.query(s,mid);
				long B[]=right.query(mid+1,e);
				return new long[]{A[0]+B[0],A[1]+B[1]};
                
            }
        }
 
        public void update(int index,int v){
			sum+=v;
			cnt++;
            if(l==r&&l==index){
                return;
            }
            int mid=l+(r-l)/2;
            if(index<=mid){
				if(left==null)left=new Seg(l,mid);
                left.update(index,v);
            }else{
				if(right==null)right=new Seg(mid+1,r);
                right.update(index,v);
            }
            
        }
    }