#include <bits/stdc++.h>

using namespace std;

int main() {

    string s;
    string graph[7] =
    {
        "1100110000000000",
        "1000100010001000",
        "1111000000000000",
        "0100110010000000",
        "1100011000000000",
        "1000110001000000",
        "0110110000000000"
    };

    int find;
    char field[8][9];

    while(cin >> field[0]) {

        s = "";
        find = 0;

        for(int i = 1; i < 8; ++i) {
            cin >> field[i];
        }

        for(int i = 0; i < 8 && find == 0; ++i) {
            for(int j = 0; j < 6 && find == 0; ++j) {
                if(field[i][j] == '1' || field[i][j + 1] == '1' && field[i - 1][j] == '1') {
                    find = 1;
                    for(int k = i; k < i + 4; ++k) {
                        for(int l = j; l < j + 4; ++l) {
                            s += field[k][l];
                        }
                    }
                }
            }
        }

        for(int i = 0; i < 7; ++i) {
            if(s == graph[i]) {
                cout << (char)('A' + i) << endl;
                break;
            }
        }

    }

}