N,M=map(int,input().split())
result=[[0]*M for i in range(N)]
for i in range(N):
  for j in range(M):
    a=i%2
    b=(j//2)%2
    if a==b:
      result[i][j]='O'
    else:
      result[i][j]='X'
  print(*result[i],sep='')