#include<bits/stdc++.h> using namespace std; int main() { int n,x; cin>>n>>x; int a[200005]; for(int i=0;i<n;i++)cin>>a[i]; int l=0,r=n-1,ans=-1; while(l<=r) { int mid=(l+r)/2; if(a[mid]==x)ans=mid+1,r=mid-1; else if(a[mid]<x)l=mid+1; else r=mid-1; } cout<<ans; return 0; }