#include <bits/stdc++.h>
using namespace std;
int main()
{
int g, s, b, t;
cin >> g >> s >> b >> t;
if (t < g)
cout << "gold";
else if (t < s)
cout << "silver";
else if (t < b)
cout << "bronze";
else
cout << "none";
cout << "\n";
return 0;
}
