/******************************************************************************

                              Online C++ Compiler.
               Code, Compile, Run and Debug C++ program online.
Write your code in this editor and press "Run" button to compile and execute it.

*******************************************************************************/

#include <iostream>

using namespace std;

int main()
{
    unsigned int v[100000]={1},n,x,l,r,m;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>v[i];
    }
    cin>>x;
    l=1;
    r=n;
    while(l<=r){
        m=(l+r)/2;
        if(x<v[m])r=m-1;
        else if(x>v[m])l=m+1;
        else if(x==v[m]){
        cout<<m;
            l=r;
        }
    }
    
    return 0;
}