#include<bits/stdc++.h>
using namespace std;
int n,x,a[100001];
int main(){
	cin>>n>>x;
	int i=1,j=n,mid;
	for(int i=1;i<=n;i++)
		cin>>a[i];
	while(i<=j){
		mid=i+(j-i)/2;
		if(a[mid]==x){
			cout<<mid;
			return 0;
		}
		if(a[mid]<x) j=mid-1;
		else if(a[mid]>x) i=mid+1;
	}
	cout<<"Yah that’s a stupid ice elf!"; 
    return 0;
}

二分查找(bs)