#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define debug(...) ((void)0)

using namespace std;
using ll = long long;
using ld = long double;

void solve(int) {
    int N;
    string S;
    cin >> N >> S;

    for (int i = 0; i + 2 < N; i++) {
        if (S[i] == '4' && S[i + 1] == '0' && S[i + 2] == '4') {
            cout << "Found" << endl;
            return;
        }
    }

    cout << "NotFound" << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    solve(0);
}