#include <iostream>
using namespace std;
int main()
{
for(int x=0; x<3; x++)
{
int Sum=0,a;
for(int y=0; y<4; y++)
{
cin>>a;
Sum+=a;
}
switch(Sum)
{
case 0: cout<<"D";break;
case 1: cout<<"C";break;
case 2: cout<<"B";break;
case 3: cout<<"A";break;
case 4: cout<<"E";break;
}
cout<<endl;
}
}