#include <iostream>
#include <string>
#include <cassert>
using namespace std;
using ll = long long;
template<class T> inline bool chmax(T& a, const T& b) {if (a<b) {a=b; return true;} return false;}
template<class T> inline bool chmin(T& a, const T& b) {if (b<a) {a=b; return true;} return false;}
const int INTINF = 1000001000;
const int INTMAX = 2147483647;
const ll LLMAX = 9223372036854775807;
const ll LLINF = 1000000000000000000;

int main() {
  ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  int N; cin >> N;
  string S; cin >> S;
  for (int i=0; i+3<N; i++) {
    if (S.substr(i,3) == "404") {
      cout << "Found\n";
      return 0;
    }
  }
  cout << "NotFound\n";
  return 0;
}