#include <iostream.h>
#include <fstream>
#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>
#include <functional>
#include <list>
#include <cstdio>
#include <cmath>
#include <cstdlib>

using namespace std; 

int main()
{
    ifstream fin("DATA2.txt");
    ofstream fout("OUT2.txt");
    
    for(int k = 0;k < 5; k++)
    {
    char tick[3][3];
    
    for(int i = 0; i < 3; i++)
    {
            for(int j = 0; j < 3; j++)
            {
                    fin >> tick[i][j];
            }
    }
    if(tick[0][0] == tick[0][1] && tick[0][0] == tick[0][2] && tick[0][0] != '.')
                  fout << tick[0][0] << endl;
    else if (tick[1][0] == tick[1][1] && tick[1][0] == tick[1][2] && tick[1][0] != '.')
                        fout << tick[1][0] << endl;
    else if (tick[2][0] == tick[2][1] && tick[2][0] == tick[2][2] && tick[2][0] != '.')
                        fout << tick[2][0] << endl;
    else if (tick[0][0] == tick[1][0] && tick[1][0] == tick[2][0] && tick[2][0] != '.')
                        fout << tick[0][0] << endl;
    else if (tick[0][1] == tick[1][1] && tick[1][1] == tick[2][1] && tick[2][1] != '.')
                        fout << tick[0][1]<< endl;
    else if (tick[0][2] == tick[1][2] && tick[1][2] == tick[2][2] && tick[2][2] != '.')
                        fout << tick[0][2]<< endl;
    else if (tick[0][0] == tick[1][1] && tick[1][1] == tick[2][2] && tick[2][2] != '.')
                        fout << tick[0][0]<< endl;
    else if (tick[0][2] == tick[1][1] && tick[1][1] == tick[2][0] && tick[2][0] != '.')
                        fout << tick[0][2]<< endl;
    else
                        fout << "." << endl;
    }

}