C++ :

#include<bits/stdc++.h>
using namespace std;
int main() {
 int x;
 cin>>x;
 if(x % 4 == 1) cout<<"D";
 else if(x % 4 == 2) cout<<"F";
 else if(x % 4 == 3) cout<<"B";
 else if(x % 4 == 0) cout<<"Y";
return 0;
}