H, W = map(int, input().split())

ans = [[""]*W for _ in range(H)]
for i in range(H):
    for j in range(W):
        if (i+j//2)%2 == 0:
            ans[i][j] = "O"
        else:
            ans[i][j] = "X"

for a in ans:
    print("".join(a))