#include <iostream>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <vector>
#include <string>
#include <queue>
#include <functional>
#include <numeric>

using namespace std;

string ans;
char grid[2][30];

void output()
{
    for(int i = 0; i < 30; i++){
       cout << grid[0][i];
    }
    cout << endl;
    for(int i = 0; i < 30; i++){
       cout << grid[1][i];
    }
    cout << endl;     
}

string backwards( string fido )
{
string fard = "";
    for (int i=fido.length();i>0;i--){ 
        fard += fido[i-1];
    }
    return fard;
}

bool recur(int i)
{
     if (i >= 30)
        return true;
    if( grid[0][i] == 'x' && grid[0][i+1] == '.' && grid[1][i] == 'x' && grid[1][i+1] == 'x' ){
        ans += 'A';
        if (!recur(i+2))
           ans = ans.substr(0, ans.length()-1);
        else
            return true;
    }
    else if( grid[0][i] == 'x' && grid[0][i+1] == 'x' && grid[1][i] == 'x' && grid[1][i+1] == 'x' ){
        ans += 'B';
        if (!recur(i+2))
           ans = ans.substr(0, ans.length()-1);
        else
            return true;
    }
    if( grid[0][i] == 'x' && grid[0][i+1] == '.' && grid[1][i] == 'x' && grid[1][i+1] == 'x' && grid[0][i+2] != 'x' && grid[1][i+2] != 'x'){
        ans += 'C';
        if (!recur(i+3))
           ans = ans.substr(0, ans.length()-1);
        else
            return true;
    }
    if( grid[0][i] == 'x' && grid[0][i+1] == 'x' && grid[1][i] == '.' && grid[1][i+1] == 'x' ){
         ans += 'D';
        if (!recur(i+2))
           ans = ans.substr(0, ans.length()-1);
        else
            return true;
    }
    if ( grid[0][i] == 'x' && grid[0][i+1] == 'x' && grid[1][i] == '.' && grid[1][i+1] == 'x' && grid[0][i+2] != 'x' && grid[1][i+2] != 'x' ){
         ans += 'E';
         if (!recur(i+3))
           ans = ans.substr(0, ans.length()-1);
        else
            return true;
    }
    return false;
    cout << ans << endl;
}

int main()
{
    freopen("DATA4.txt", "r", stdin);
    freopen("OUT4.txt", "w", stdout); 
    
    string L[2], input,output;
    for (int t=0;t<5;t++)
    {
        for (int i=0;i<2;i++)
        {
            cin>>L[i];
            L[i]=backwards(L[i]);
        }
        input="";
        output="";
        for (int i=0;i<L[0].length();i++)
        {
            if (L[0][i]=='x')
            {
                if (L[1][i]=='x') input+="2";
                else input+="0";
            }
            else input+="1";
        }
        while (input.length()!=0)
        {
            if (input.substr(0,3)=="220")
            {
                output+="E";
                input=input.substr(3,input.length()-3);
            }
            else if (input.substr(0,3)=="212")
            {
                output+="C";
                input=input.substr(3,input.length()-3);
            }
            else if (input.substr(0,2)=="22")
            {
                output+="B";
                input=input.substr(2,input.length()-2);
            }
            else if (input.substr(0,2)=="20")
            {
                output+="D";
                input=input.substr(2,input.length()-2);
            }
            else if (input.substr(0,2)=="12")
            {
                output+="A";
                input=input.substr(2,input.length()-2);
            }
        }
        cout<< backwards(output)<<endl;
    }
    
	return 0;
}