#nullable enable

#region
var _input = Array.Empty<string>();
var _iter = 0;
string String()
{
    while (_iter >= _input.Length) (_input, _iter) = (Console.ReadLine()!.Split(' '), 0);
    return _input[_iter++];
}
T I<T>() where T : IParsable<T> => T.Parse(String(), null);
#endregion

string Join<T>(IEnumerable<T> values, bool ws = false) => string.Join(ws ? " " : Environment.NewLine, values);

var h = I<int>();
var w = I<int>();

var res = new string[h];
for (var i = 0; i < h; i++)
{
    var row = new char[w];
    var x = (i & 2) >> 1;
    for (var j = 0; j < w; j++)
    {
        var y = j & 1;
        row[j] = (x ^ y) == 0 ? 'O' : 'X';
    }
    res[i] = new(row);
}
Console.WriteLine(Join(res));