h, w = map(int, input().split())

S = [[0 for _ in range(w)] for _ in range(h)]

for i in range(h):
    for j in range(w):
        if i % 2 == 0:
            if j % 4 < 2:
                S[i][j] = "O"
            else:
                S[i][j] = "X"
        else:
            if j % 4 < 2:
                S[i][j] = "X"
            else:
                S[i][j] = "O"

for s in S:
    print("".join(s))