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

A=[]
B=[]
for i in range(W):
  if i%2==0:
    A.append('O')
    B.append('X')
  else:
    A.append('X')
    B.append('O')
    
ans=[]
for i in range(H):
  if i%4<2:
    print(''.join(A))
  else:
    print(''.join(B))