#include<iostream>
#include<cmath>
#include<math.h>
#include<string>
#include <fstream>
#include <cctype>
#include <iomanip>
#include <algorithm>
using namespace std;
int main()
{
	int x,y,z;
	char board[3][3];
	freopen("DATA2.txt","r",stdin);
	freopen("OUT2.txt","w",stdout);
	for(z=0;z<5;z++)
	{
		for(x=0;x<3;x++)
			for(y=0;y<3;y++)
				cin >> board[x][y];
		if(board[0][0]==board[0][1] && board[0][1]==board[0][2])
			cout << board[0][1] << endl;
		else if(board[1][0]==board[1][1] && board[1][1]==board[1][2])
			cout << board[1][1] << endl;
		else if(board[2][0]==board[2][1] && board[2][1]==board[2][2])
			cout << board[2][1] << endl;
		else if(board[0][0]==board[1][0] && board[1][0]==board[2][0])
			cout << board[1][0] << endl;
		else if(board[0][1]==board[1][1] && board[1][1]==board[2][1])
			cout << board[0][1] << endl;
		else if(board[0][2]==board[1][2] && board[1][2]==board[2][2])
			cout << board[1][2] << endl;
		else if(board[0][0]==board[1][1] && board[1][1]==board[2][2])
			cout << board[1][1] << endl;
		else if(board[0][2]==board[1][1] && board[1][1]==board[2][0])
			cout << board[1][1] << endl;
		else
			cout << "." << endl;
	}
	return(0);
}