#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: admin
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/