#include <iostream>
#include <stdio.h>
#include <string>
#include <math.h>
#include <algorithm>
#include <vector>
#include <map>
#include <cstdio>
#include <utility>

using namespace std;
typedef pair<double,double> P;




int main(){
	int field[8][8];
	string field1[8];
	int count = 0;
	while(cin >> field1[0]){
		for(int i = 1;i < 8;i++){
			cin >> field1[i];
		}
		for(int i = 0;i < 8;i++){
			for(int j = 0;j < 8;j++){
				if(field1[i][j] == '1') field[i][j] = 1;
				else field[i][j] = 0;
			}
		}
		/*for(int i = 0;i < 8;i++){
			for(int j = 0;j < 8;j++){
				cout << field[i][j];
			}
			cout << endl;
		}
		cout << endl;*/
		for(int i = 0;i < 8;i++){
			int flag = 0;
			for(int j = 0;j < 8;j++){
				if(field[i][j] == 1){
					//cout << i << j <<endl;
					if(field[i][j] == field[i][j+1]){
						if(field[i][j] == field[i+1][j]){
							if(field[i][j] == field[i+1][j+1]){
								cout << "A" << endl;
								flag = 1;break;
							}
							else if(field[i][j] == field[i+1][j-1]){
								cout << "G" << endl;
								flag = 1;break;
							}
						}
						else if(field[i][j] == field[i][j+2] && field[i][j] == field[i][j+3]){
							cout << "C" << endl;
							flag = 1;break;
						}
						else if(field[i][j] == field[i+1][j+1] && field[i][j] == field[i+1][j+2]){
							cout << "E" << endl;
							flag = 1;break;
						}
					}
					else if(field[i][j] == field[i+1][j]){
						if(field[i][j] == field[i+1][j-1] && field[i][j] == field[i+2][j-1]){
							cout << "D" << endl;
							flag = 1;break;
						}
						else if(field[i][j] == field[i+1][j+1] && field[i][j] == field[i+2][j+1]){
							cout << "F" << endl;
							flag = 1;break;
						}
					}
					else if(field[i][j] == field[i+1][j] && field[i][j] == field[i+2][j] && field[i][j] == field[i+3][j]){
						cout << "B" << endl;
						flag = 1;break;
					}
				}
			}
			if(flag == 1) break;
		}
		count++;
	}

	return 0;
}