诏曰

#include<bits/stdc++.h>
using namespace std;
int nums[100000000],n,m;
int BinSearch(int r[],int low,int high,int num){
	int mid;
	if(low>high) return -1;
	else{
		mid=(low+high)/2;
		if(num>r[mid]) return BinSearch(r,mid+1,high,num);
		else if(num<r[mid]) return BinSearch(r,low,mid-1,num);
		else return mid;
	}
}
int main(){
	cin>>n>>m; for(int i=1;i<=n;i++) cin>>nums[i];
	cout<<BinSearch(nums,1,n,m);
	return 0;
}