using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (h, w) = (c[0], c[1]);
        var ans = new char[h][];
        for (var i = 0; i < h; ++i)
        {
            ans[i] = new char[w];
            for (var j = 0; j < w; ++j) ans[i][j] = ((i + j / 2) % 2 == 0) ? 'O' : 'X';
        }
        WriteLine(string.Join("\n", ans.Select(ai => string.Concat(ai))));
    }
}