#include <bits/stdc++.h>

using namespace std;

int main() {
    int n;
    cin >> n;
    int a[1000] = {0};
    for (int i = 0; i < n; i++) {
        cin >> a[i];
    }
    int x;
    cin >> x;
    bool found = false;
    for (int i = 0; i < n; i++) {
        if (a[i] == x) {
            cout << i + 1 << endl;
            found = true;
            break;
        }
    }
    if (!found) cout << -1 << endl;
    return 0;
}