Go: package main

import (
	"bufio"
	"os"
	"strings"
	"strconv"
	"reflect"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

func scanBoard() [][]int {
	ret := make([][]int, 8)
	for k := range ret {
		ret[k] = make([]int, 8)
		for l := range ret[k] {
			ret[k][l] = 0
		}
	}
	for i := 0; i < 8; i++ {
		scanner.Scan()
		row := strings.Split(scanner.Text(), "")
		for j := 0; j < 8; j++ {
			ret[i][j], _ = strconv.Atoi(row[j])
		}
	}
	return ret
}

func main() {
	for {
		var board [][]int
		var ans string
		if board = scanBoard(); reflect.DeepEqual(board, [][]int{}) {
			break
		}
		fmt.Println(board)
		for i := 0; i < 7; i++ {
			for j := 0; j < 7; j++ {
				if board[i][j] == 1 && board[i+1][j] == 1 && board[i][j+1] == 1 && board[i+1][j+1] == 1 {
					ans = "A"
				}
			}
		}
		for i := 0; i < 5; i++ {
			for j := 0; j < 8; j++ {
				if board[i][j] == 1 && board[i+1][j] == 1 && board[i+2][j] == 1 && board[i+3][j] == 1 {
					ans = "B"
				}
			}
		}
		for i := 0; i < 8; i++ {
			for j := 0; j < 5; j++ {
				if board[i][j] == 1 && board[i][j+1] == 1 && board[i][j+2] == 1 && board[i][j+3] == 1 {
					ans = "C"
				}
			}
		}
		for i := 0; i < 6; i++ {
			for j := 0; j < 7; j++ {
				if board[i][j+1] == 1 && board[i+1][j] == 1 && board[i+1][j+1] == 1 && board[i+2][j] == 1 {
					ans = "D"
				}
			}
		}
		for i := 0; i < 7; i++ {
			for j := 0; j < 6; j++ {
				if board[i][j] == 1 && board[i][j+1] == 1 && board[i+1][j+1] == 1 && board[i+1][j+2] == 1 {
					ans = "E"
				}
			}
		}
		for i := 0; i < 7; i++ {
			for j := 0; j < 6; j++ {
				if board[i][j+1] == 1 && board[i][j+2] == 1 && board[i+1][j] == 1 && board[i+1][j+1] == 1 {
					ans = "G"
				}
			}
		}
		for i := 0; i < 6; i++ {
			for j := 0; j < 7; j++ {
				if board[i][j] == 1 && board[i+1][j] == 1 && board[i+1][j+1] == 1 && board[i+2][j+1] == 1 {
					ans = "F"
				}
			}
		}
		fmt.Println(ans)
	}
}

C++: #define	_USE_MATH_DEFINES
#include <iostream>
#include <algorithm>
#include <functional>
#include <vector>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <cfloat>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <string>
#include <set>
using namespace std;
char s[100][100];
int main(){
	

	while(cin>>s[1][1]){
		int x,y;
		bool f=false;
		for(int j=2;j<8;j++)
			cin>>s[1][j];
		for(int i=2;i<=8;i++){
			for(int j=1;j<=8;j++){
				cin>>s[i][j];
				if(s[i][j]=='1'&&!f){
					y=i;
					x=j;
					f=true;
				}
			}
		}
		
		if(s[y][x]=='1'&&s[y+1][x]=='1'&&s[y][x+1]=='1'&&s[y+1][x+1]=='1')
			cout<<"A"<<endl;
		else if(s[y][x]=='1'&&s[y+1][x]=='1'&&s[y+2][x]=='1'&&s[y+3][x]=='1')
			cout<<"B"<<endl;
		else if(s[y][x]=='1'&&s[y][x+1]=='1'&&s[y][x+2]=='1'&&s[y][x+3]=='1')
			cout<<"C"<<endl;
		else if(s[y][x]=='1'&&s[y+1][x]=='1'&&s[y+1][x-1]=='1'&&s[y+2][x-1]=='1')
			cout<<"D"<<endl;
		else if(s[y][x]=='1'&&s[y][x+1]=='1'&&s[y+1][x+1]=='1'&&s[y+1][x+2]=='1')
			cout<<"E"<<endl;
		else if(s[y][x]=='1'&&s[y+1][x]=='1'&&s[y+1][x+1]=='1'&&s[y+2][x+1]=='1')
			cout<<"F"<<endl;
		else if(s[y][x]=='1'&&s[y][x+1]=='1'&&s[y+1][x]=='1'&&s[y+1][x-1]=='1')
			cout<<"G"<<endl;
		
	}
}

C++: #include<iostream>
#include<string>

using namespace std;

int main()
{
	int k = 0;
	for(;;){
		char MAP[8][8];
		int cont = 0;
		int air_cont = 0;
		bool canCont = false;
		
		for(int i = 0; i < 8; i++){
			for(int j = 0; j < 8; j++){
				cin >> MAP[i][j];
				if(cin.eof()){
					exit(1);
				}
			}
		}
		//ツ債カツ端ツづーツ個ゥツづつつッツづつゥツづァツ催古」ツづ個ブツδ債ッツクツつェツ個ゥツづつつゥツづゥツづ慊づづ個凝ウツ板陳青板づーツ記ツ録
		for(int i = 0; i < 8; i++){
			for(int j = 0; j < 8; j++){
				if(MAP[i][j] == '1'){
					cont++;
					if(cont == 1){
						canCont = true;
					}
					if(cont == 4){
						//ツδ仰ーツプツ仰ュツ青ァツ終ツ猟ケ
						goto FIN;
					}
				}
				else if(canCont == true && MAP[i][j] == '0'){
					air_cont++;
				}
			}
		}
		
		FIN:;
		
		switch(air_cont){
			case 0:
				cout << "C" << endl;
				break;
			case 5:
				cout << "G" << endl;
				break;
			case 6:
				cout << "A" << endl;
				break;
			case 7:
				cout << "E" << endl;
				break;
			case 12:
				cout << "D" << endl;
				break;
			case 14:
				cout << "F" << endl;
				break;
			case 21:
				cout << "B" << endl;
				break;
			default:
				cout << "NA" << endl;
		}
	}
}

C++: #include<iostream>
#include<string>
#include<cstdio>
using namespace std;
char n[12][12];
char figure[7][4][4] = {
	{"1100","1100","0000","0000"},
	{"1000","1000","1000","1000"},
	{"1111","0000","0000","0000"},
	{"0100","1100","1000","0000"},
	{"1100","0110","0000","0000"},
	{"1000","1100","0100","0000"},
	{"0110","1100","0000","0000"}
};
int main(){
	for(int i=0; i<12; i++)
		for(int j=0; j<12; j++)
			n[i][j]='0';
	
	while(~scanf("%8s\n%8s\n%8s\n%8s\n%8s\n%8s\n%8s\n%8s\n\n", n[0], n[1], n[2], n[3], n[4], n[5], n[6], n[7])){
		for(int i=0; i<8; i++)
			for(int j=0; j<8; j++)
				cin >> n[i][j];

		for(int i=0; i<7; i++){
			for(int j=0; j<8; j++){
				for(int k=0; k<8; k++){
					bool flag=true;
					
					for(int x=0; x<4; x++){
						for(int y=0; y<4; y++){
							if(figure[i][x][y] != n[j+x][k+y]) flag = false;
						}
					}
					
					if(flag){
						cout << (char)('A'+i) << endl;
					}

				}
			}
		}
	}
	return 0;
}

C++: /*#include<iostream>
#include<string>
#include<vector>
#include<cstdio>
#include<sstream>
#include<algorithm>
#include<cmath>
#include<map>
#include<functional>
#include<queue>
#include<stack>
#include<set>
using namespace std;
int main(){
int n;
cin>>n;
for(int i=0;i<n;i++){
	double x1,y1,x2,y2,x3,y3,x4,y4;
	bool f=0;
	cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4;
	double yy1=(y2-y1),yy2=y4-y3;
	if(yy1==0)yy1=0.0000001;
	if(yy2==0)yy2=0.0000001;
	double r1=(x2-x1) / (y2-y1);
	double r2=(x4-x3) / (y4-y3);
	if(abs(r1-r2 ) <=0.000001  )f=1;
	if(f)cout<<"YES"<<endl;
	else cout<<"NO"<<endl;
	}
	return 0;
}*/

/*#include<iostream>
#include<string>
#include<vector>
#include<cstdio>
#include<sstream>
#include<algorithm>
#include<cmath>
#include<map>
#include<functional>
#include<queue>
#include<stack>
#include<set>
using namespace std;
int stoi(string x){stringstream ss;ss<<x;int tmp;ss>>tmp;return tmp;}
string itos(int x){stringstream ss;ss<<x;return ss.str();}
char ta[50][50];
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
char a[]={'R','D','L','U'};
vector<char>ans;
void dfs(int y,int x,char now){
	bool f=1;
	for(int i=0;i<4;i++){
		if(a[i]==now&&ta[y+dy[i]][x+dx[i]]=='1'){
			ans.push_back(a[i]);
			f=1;
			dfs(y+dy[i],x+dx[i],now);
		}
	}
	if(f){
		for(int i=0;i<4;i++){
			if(ta[y+dy[i]][x+dx[i]]=='1'){
				ans.push_back(a[i]);
				dfs(y+dy[i],x+dx[i],a[i]);
			}
		}
	}
}

int main(){


	for(int i=0;i<9;i++){
		for(int j=0;j<4;j++){
			char now;
			cin>>now;
			ta[i][j]=now;
		}
	}
		dfs(0,0,'F');
		for(int i=0;i<ans.size();i++)cout<<ans[i];
		ans.clear();
	return 0;
}*/


#include<iostream>
#include<string>
#include<vector>
#include<cstdio>
#include<sstream>
#include<algorithm>
#include<cmath>
#include<map>
#include<functional>
#include<queue>
#include<stack>
#include<set>
using namespace std;
int stoi(string x){stringstream ss;ss<<x;int tmp;ss>>tmp;return tmp;}
string itos(int x){stringstream ss;ss<<x;return ss.str();}
char ta[8][8];
int main(){
while(cin>>ta[0][0]){
	int y,x;
	bool f=1;
	for(int i=0;i<8;i++){
		for(int j=(i==0);j<8;j++){
			char now;
			cin>>now;
			if(now=='1'&&f){y=i,x=j;f=0;}
			ta[i][j]=now;
		}
	}
	//for(int i=0;i<8;i++){for(int j=0;j<8;j++){cout<<ta[i][j];}cout<<endl;}
	if(ta[y][x+1]=='1'&&ta[y+1][x]=='1'&&ta[y+1][x+1]=='1')cout<<"A";
	
	else if(ta[y+1][x]=='1'&&ta[y+2][x]=='1'&&ta[y+3][x]=='1')cout<<"B";
	
	else if(ta[y][x+1]=='1'&&ta[y][x+2]=='1'&&ta[y][x+3]=='1')cout<<"C";
	
	else if(ta[y][x+1]=='1'&&ta[y+1][x+1]=='1'&&ta[y+1][x+2]=='1')cout<<"E";
	
	else if(ta[y+1][x]=='1'&&ta[y+1][x+1]=='1'&&ta[y+2][x+1]=='1')cout<<"F";
	
	else if(ta[y][x+1]=='1'&&ta[y+1][x]=='1'&&ta[y+1][x-1]=='1')cout<<"G";
	
	else if(ta[y+2][x-1]=='1'&&ta[y+1][x]=='1'&&ta[y+1][x-1]=='1')cout<<"D";

	cout<<endl;
		for(int i=0;i<8;i++)for(int j=0;j<8;j++)ta[i][j]='0';
}
	
	return 0;
}