#include <iostream>
using namespace std;
int main()
{
	int n, a[100], x, cnt = -1;
	cin >> n;
	for (int i = 0; i < n; i++)
    	cin >> a[i];
	cin >> x;
	for (int i = 0; i < n; i++)
		if (a[i] == x)
			cnt = i + 1;
	cout << cnt;
    return 0;
}