#include<cstdio>
#include<cmath>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<iostream>

using namespace std;

char s[15][15];

char Solution(int i, int j)
{
    if(s[i][j]=='1' && s[i + 1][j] == '1' && s[i][j + 1] == '1' && s[i + 1][j + 1] == '1')
    {
        return 'A';
    }
    
    if(s[i][j] == '1' && s[i + 1][j] == '1' && s[i + 2][j] == '1' && s[i + 3][j] == '1')
    {
        return 'B';
    }
    
    if(s[i][j] == '1' && s[i][j + 1] == '1' && s[i][j + 2] == '1' && s[i][j + 3] == '1')
    {
        return 'C';
    }
    
    if(s[i][j] == '1' && s[i][j + 1] == '1' && s[i + 1][j + 1] == '1' && s[i + 1][j + 2] == '1')
    {
        return 'E';
    }
    
    if(s[i][j] == '1' && s[i + 1][j] == '1' && s[i + 1][j + 1] == '1'&&s[i + 2][j + 1] == '1')
    {
        return 'F';
    }
    
    if(j > 0)  // can not start from j = 0
    {
        if(s[i][j] == '1' && s[i + 1][j] == '1' && s[i + 1][j - 1] == '1' && s[i + 2][j - 1] == '1')
        {
            return 'D';
        }
        
        if(s[i][j] == '1' && s[i + 1][j] == '1' && s[i + 1][j - 1] == '1' && s[i][j + 1] == '1')
        {
            return 'G';
        }
    }
    
    return 0;
}

int main()
{
    while(!cin.eof())  // tests for end-of-file
    {
        
        for(int i = 0; i < 15; i++)
        {
            for(int j = 0; j < 15; j++)
            {
                s[i][j] = '0';
            }
        }
        
        for(int i = 0; i < 8; i++)
        {
            for (int j = 0 ; j < 8; j++)
            {
                cin>>s[i];
            }

        }
        
        char figure;
        
        bool solved = true;
        
        for(int i=0;i<8;i++)
        {
            for(int j=0;j<8;j++)
            {
                if(s[i][j]!='1')
                {
                    continue;
                }
                
                if(solved)
                {
                    figure = Solution(i, j);
                    
                    cout<<figure<<endl;
                    
                    solved = false;
                }
            }
        }
    }
    return 0;
}