#include<iostream>
#include<string>
using namespace std;

int main(){
	string line[8];

	while(1){


		int w = 0, h = 0, t=-1;

		for(int i=0;i<8;++i)
			cin >> line[i];

		int right=0,left=7;

		for(int i=0;i<8;++i){
			bool exist = false;
			for(int j=0;j<8;++j){
				if((line[i])[j] == '1'){
					if(t!=-1)t=i;
					if(j>right)right = j;
					if(j<left)left = j;
					exist = true;
				}
			}
			if(exist)++h;
		}
		w = right - left + 1;

		if( w == 2 && h == 2 )cout<<"A"<<endl;
		else if(w == 1)cout<<"B"<<endl;
		else if(h == 1)cout<<"C"<<endl;


		else if(w==2){
			for(int i=0;i<8;++i){
				if((line[i])[left] == '1'){
					if((line[i])[left+1]=='1')
						cout<<"D"<<endl;
					else
						cout<<"F"<<endl;
					break;
				}
			}
		}

		else if(h==2){
			for(int i=0;i<8;++i){
				if((line[t])[i]=='1'){
					if((line[t+1])[i]=='1')
						cout<<"G"<<endl;
					else
						cout<<"E"<<endl;
				}
			}
		}

	}
	return 0;
}