#include<bits/stdc++.h>
using namespace std;
int main(){
	string s;
	int n;
	cin >> n >> s;
	for(int i=0;i<n-2;i++){
		if(s[i]=='4'&&s[i+1]=='0'&&s[i+2]=='4'){cout << "Found"<< endl; return 0;}
		cout << "NotFound" << endl;
		return 0;
	}
}