#include <atcoder/all>
#include <bits/stdc++.h>
#define rep(i, a, b) for (ll i = (ll)(a); i < (ll)(b); i++)
using namespace atcoder;
using namespace std;

typedef long long ll;

int main() {
    int n;
    string s;
    cin >> n >> s;
    rep(i, 0, n - 2) {
        if (s.substr(i, 3) == "404")
            cout << "Found" << endl, exit(0);
    }
    cout << "NotFound" << endl;
}