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(), "")
		if reflect.DeepEqual(row, []string{}) {
			break
		}
		for j := 0; j < 8; j++ {
			ret[i][j], _ = strconv.Atoi(row[j])
		}
	}
	return ret
}

var emptyBoard = [][]int{{0,0,0,0,0,0,0,0},
						 {0,0,0,0,0,0,0,0},
						 {0,0,0,0,0,0,0,0},
	                     {0,0,0,0,0,0,0,0},
	                     {0,0,0,0,0,0,0,0},
	                     {0,0,0,0,0,0,0,0},
	                     {0,0,0,0,0,0,0,0},
	                     {0,0,0,0,0,0,0,0}}

func main() {
	for {
		var board [][]int
		var ans string
		if board = scanBoard(); reflect.DeepEqual(board, emptyBoard) {
			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)
		fmt.Scanln()
	}
}

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;
}

C++:  
 #include<iostream>
 #include<stdio.h>
 #include<string>
 #include<math.h>
 #include<iomanip>
 #include<algorithm>
 #include<string.h>
 #include<cctype>
 #include<map>
 #include<set>
 #include<vector>
 #include<sstream>
 #include<stack>
 #include<queue>
 
 using namespace std;

 int arr[8][8];
 
 int main()
 {
   while(cin>>arr[0][0])
   {
     int x[4],y[4];
     int cnt1,cnt2;
     cnt1=cnt2=0;
     if(arr[0][0]==1)
     {
       x[cnt1++]=0;
       y[cnt2++]=0;                
     }
     for(int i=0;i<8;i++)
     {
       for(int j=0;j<8;j++)
       {
         if(i==0&&j==0) continue;
         else
         {
           if(arr[i][j]==1)
           {
             x[cnt1++]=i;
             y[cnt2++]=j;                
           }    
         }        
       }        
     }             
     if(y[0]==y[1]&&y[2]==y[3]&&x[1]==x[0]+1&&x[3]==x[2]+1) cout<<"A"<<endl;
     else if(x[0]==x[1]&&x[1]==x[2]&&x[2]==x[3]) cout<<"B"<<endl;
     else if(y[0]==y[1]&&y[1]==y[2]&&y[2]==y[3]) cout<<"C"<<endl;
     else if(y[1]==y[2]&&x[0]==x[3]+1) cout<<"D"<<endl;
     else if(x[1]==x[2]&&x[3]==x[0]+2) cout<<"E"<<endl;
     else if(y[1]==y[2]&&y[3]==y[0]+1) cout<<"F"<<endl;
     else cout<<"G"<<endl;        
   }
   //while(1);
   return 0;
 }

C++: #include <iostream>

using namespace std;

char p[8][9];

bool m(int i, int j) {
  return 0 <= i && i < 8 && 0 <= j && j < 8 && p[i][j] == '1';
}

int main() {
  while (cin >> p[0], !cin.eof()) {
    for (int i = 1; i < 8; i++)
      cin >> p[i];
    for (int i = 0; i < 8; i++)
      for (int j = 0; j < 8; j++)
        if (m(i, j)) {
          if (m(i, j+1) && m(i+1, j) && m(i+1, j+1))
            cout << 'A' << endl;
          else if (m(i+1, j) && m(i+2, j) && m(i+3, j))
            cout << 'B' << endl;
          else if (m(i, j+1) && m(i, j+2) && m(i, j+3))
            cout << 'C' << endl;
          else if (m(i+1, j) && m(i+1, j-1) && m(i+2, j-1))
            cout << 'D' << endl;
          else if (m(i, j+1) && m(i+1, j+1) && m(i+1, j+2))
            cout << 'E' << endl;
          else if (m(i+1, j) && m(i+1, j+1) && m(i+2, j+1))
            cout << 'F' << endl;
          else
            cout << 'G' << endl;
          goto epilogue;
        }
epilogue:;
  }
}