#include<iostream>
using namespace std;
int main()
{
int t = 0;
while (cin >> t)
{
if (t > 100 || t < 0)
{
cout << "Score is error!" << endl;
}
else
{
switch (t / 10)
{
case 10:
case 9: cout << 'A' << endl; break;
case 8: cout << 'B' << endl; break;
case 7: cout << 'C' << endl; break;
case 6: cout << 'D' << endl; break;
case 5:;
case 4:;
case 3:;
case 2:;
case 1:;
case 0: cout << 'E' << endl; break;
default: cout << "Score is error!" << endl; break;
}
}
}
return 0;
}
