#include <vector>
#include <iostream>
#include <string>
#include <ostream>
#include <map>
#include <set>
#include <bitset>
#include <cmath>
#include <iomanip>
#include <algorithm>
#include <list>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;

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