#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)

template<typename T>
bool chmin(T &x, T y) { return x > y ? (x = y, true) : false; }
template<typename T>
bool chmax(T &x, T y) { return x < y ? (x = y, true) : false; }

struct io_setup {
	io_setup() {
		ios::sync_with_stdio(false);
		std::cin.tie(nullptr);
		cout << fixed << setprecision(15);
	}
} io_setup;

int main(){
	int n;
	string s;
	cin>>n>>s;
	rep(i,0,n-2){
		if(s.substr(i,3)=="404"){
			cout<<"Found\n";
			return 0;
		}
	}
	cout<<"Not Found\n";
}