h, w = map(int, input().split())
m = ['O', 'X']
i = 0
f = 0
while i < h:
    s = ''
    for j in range(w):
        s += m[f]
        f ^= 1
    if w % 2 == 0:
        f ^= 1
    print(s)
    if i + 2 <= h:
        print(s)
    i += 2