#include <iostream>

using namespace std;

/** Problem0036 : A Figure on Surface **/
int main()
{
	char board[8][9];
	
	while (1) {
		for (int i=0; i<8; i++)
			for (int j=0; j<8; j++)
				cin >> board[i][j];
		
		if (cin.eof()) break;
		
		for (int y=0; y<8; y++) {
			for (int x=0; x<8; x++) {
				if (board[y][x] == '1') {
					if (board[y][x+1] == '1' && board[y+1][x] == '1' && board[y+1][x+1] == '1')
						cout << "A" << endl;
					else if (board[y+1][x] == '1' && board[y+2][x] == '1' && board[y+3][x] == '1')
						cout << "B" << endl;
					else if (board[y][x+1] == '1' && board[y][x+2] == '1' && board[y][x+3] == '1')
						cout << "C" << endl;
					else if (board[y+1][x] == '1' && board[y+1][x-1] == '1' && board[y+2][x-1] == '1')
						cout << "D" << endl;
					else if (board[y][x+1] == '1' && board[y+1][x+1] == '1' && board[y+1][x+2] == '1')
						cout << "E" << endl;
					else if (board[y+1][x] == '1' && board[y+1][x+1] == '1' && board[y+2][x+1] == '1')
						cout << "F" << endl;
					else
						cout << "G" << endl;
					goto endloop;
				}
			}
		}
	endloop:
		;
	}
	
	return 0;
}