using System;
public class Program
{
public static void Main()
string frstStr = "X";
string secStr = "O";
string tempStr = "X";
for(int i= 1; i < 9; i++)
for(int j= 1; j < 9; j++)
if(j % 2 == 0)
Console.Write(secStr);
else
Console.Write(frstStr);
}
frstStr = secStr;
secStr = tempStr;
tempStr = frstStr;
Console.WriteLine();