#include<iostream>
using namespace std;
int main()
{
int a;
cin >> a;
if (a >= 90 && a <= 100)
{
cout << "A";
}
else if (a >= 80 && a < 90)
{
cout << "B";
}
else if (a >= 70 && a < 80)
{
cout << "C";
}
else if (a >= 60 && a < 70)
{
cout << "D";
}
else if (a >= 0 && a < 60)
{
cout << "E";
}
else
{
cout << "You are so funny!";
}
return 0;
}
