H,W=map(int,input().split())
ans=[["O" for _ in range(W)] for _ in range(H)]
D=[0,1,1,0]
for h in range(H):
    for w in range(D[h%4],W,2):
        ans[h][w]="X"
        w+=2
for a in ans:
    print("".join(a))