#include<bits/stdc++.h> using namespace std; const N=10010; int a[N],n,m; bool flag=0 int search(int l,int r,int x) { while(l>r) { if(a[mid]==x)return mid; else if(a[mid>x])r=mid-1; else l=mid+1; } return -1; } int main() { cin>>n; for(int i=1;i<=n;i++)cin>>a[i]; cin>>x; cout<<search(1,n,x); }