#include<bits/stdc++.h>
using namespace std;
 
 
int main() {
    int n,a[110],m,x,p = -1;
    cin>>n;
    int i;
    for(i = 0; i < n; i++) {
        cin>>a[i];
    }
    cin>>x;
    for(i = 0; i < n; i++) {
        if(a[i] == x){
            p = i + 1;
        }
    }
     
    cout<<p;
}
/**************************************************************
	Problem: 1815
	User: wangyiyang
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2072 kb
****************************************************************/