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

int main(){
  int N;cin>>N;
  string S;cin>>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;
}