#include <iostream>
using namespace std;
 
int main()
{
    char s[16][16]={0};
    while(cin >> s[0])
    {
        int y,x; char c;
        for(y=1; y<8; y++)
        cin >> s[y];
 
        for(y=0; y<8; y++)
        for(x=0; x<8; x++)
        s[y][x]-='0';
 
        for(y=0; y<64; y++)
        if(s[y/8][y%8])break;
 
        x=y%8; y/=8;
 
             if(s[y+3][x  ]) c='B';
        else if(s[y  ][x+3]) c='C';
        else if(s[y+1][x+2]) c='E';     
        else if(s[y+2][x+1]) c='F';
        else if(s[y+1][x+1]) c='A';
        else if(s[y  ][x+1]) c='G';
        else                 c='D';
 
        cout << c << endl;
    }
}