#include <iostream>

using namespace std;

int main(void){
     char field[8][8];
     char tmp;
     int i,j;
	 while(1){
	   if(cin.eof()) return 0;
	   for(i=0;i<8;i++){
		 for(j=0;j<8;j++){
		   cin >> field[i][j];
		 }
	   }
	   
	   //»ê¼êÌ`ÉÂ¢Ä»Ê
	   //Ü¸¶ãÌ}XðT·
	   for(i=0;i<8;i++){
		 for(j=0;j<8;j++){
		   if(field[i][j]) goto NEXT;
		 }
	   }
	   
     NEXT:
	   if(field[i][j+1] && field[i][j+2] && field[i][j+3]){
		 //¡êñ
		 cout << "C" << endl;
	   }else if(field[i+1][j] && field[i+2][j] && field[i+3][j]){
		 //cêñ
		 cout << "B" << endl;
	   }else if(field[i][j+1] && field[i+1][j] && field[i+1][j+1]){
		 //³û`
		 cout << "A" << endl;
	   }else if(field[i+1][j] && field[i+1][j+1] && field[i+2][j+1]){
		 //1 0
		 //1 1
		 //0 1
		 cout << "F" << endl;
	   }else if(field[i][j+1] && field[i+1][j] && field[i+1][j-1]){
		 //0 1 1
		 //1 1 0
		 cout << "G" << endl;
	   }else if(field[i][j+1] && field[i+1][j+1] && field[i+1][j+2]){
		 //1 1 0
		 //0 1 1
		 cout << "E" << endl;
	   }else{
		 cout << "D" << endl;
	   }
	 }
	 return 0;
}