h, w = map(int, input().split())
Ans = [[""] * w for _ in range(h)]
for y in range(h):
    for x in range(w):
        if not y % 2:
            t = 1
        else:
            t = 0
        if (x // 2) % 2:
            t ^= 1
        if t:
            Ans[y][x] = "O"
        else:
            Ans[y][x] = "X"

for y in range(h):
    print("".join(Ans[y]))