#include<bits/stdc++.h>
using namespace std;
using ll=long long;

int main(){
  ll n;
  cin>>n;
  string s;
  cin>>s;
  for(ll i=0;i<n-2;i++){
    ll n1=s[i]-'0';
    ll n2=s[i+1]-'0';
    ll n3=s[i+2]-'0';
    if(n1==4&&n2==0&&n3==4){
      cout<<"Found"<<endl;
      exit(0);
    }
  }
  cout<<"NotFound"<<endl;
}