Buggy python submission (verdict: Runtime Error):
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:
???break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
   elif: W % 2 == 0:
     print ('.#'*(W//2))
    else:
     print ('.#'*(W//2)+'.')
    print ''

Fixed submission:
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if W % 2 == 0:
    print ('.#'*(W//2))
   else:
    print ('.#'*(W//2)+'.')
 print ''

Buggy python submission (verdict: Runtime Error):
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:
???break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
   else:
    if: W % 2 == 0:
     print ('.#'*(W//2))
    else:
     print ('.#'*(W//2)+'.')
    print ''

Fixed submission:
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if W % 2 == 0:
    print ('.#'*(W//2))
   else:
    print ('.#'*(W//2)+'.')
 print ''

Buggy python submission (verdict: Runtime Error):
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:
???break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if: W % 2 == 0:
    print ('.#'*(W//2))
 else:
  print ('.#'*(W//2)+'.')
print ''

Fixed submission:
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if W % 2 == 0:
    print ('.#'*(W//2))
   else:
    print ('.#'*(W//2)+'.')
 print ''

Buggy python submission (verdict: Runtime Error):
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:
???break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if: W % 2 == 0:
    print ('.#'*(W//2))
 else:
  print ('.#'*(W//2)+'.')
 print ''

Fixed submission:
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if W % 2 == 0:
    print ('.#'*(W//2))
   else:
    print ('.#'*(W//2)+'.')
 print ''

Buggy python submission (verdict: Runtime Error):
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:
???break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if: W % 2 == 0:
    print ('.#'*(W//2))
   else:
    print ('.#'*(W//2)+'.')
 print ''

Fixed submission:
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if W % 2 == 0:
    print ('.#'*(W//2))
   else:
    print ('.#'*(W//2)+'.')
 print ''

Buggy python submission (verdict: Runtime Error):
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:
???break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if W % 2 == 0:
    print ('.#'*(W//2))
   else:
    print ('.#'*(W//2)+'.')
 print ''

Fixed submission:
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if W % 2 == 0:
    print ('.#'*(W//2))
   else:
    print ('.#'*(W//2)+'.')
 print ''

Buggy python submission (verdict: Runtime Error):
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:
 break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if W % 2 == 0:
    print ('.#'*(W//2))
   else:
    print ('.#'*(W//2)+'.')
 print ''

Fixed submission:
while 1:
 H, W = map(int,raw_input().split())
 if H + W == 0:break
 for h in range(H):
  if h % 2 == 0:
   if W % 2 == 0:
    print ('#.'*(W//2))
   else:
    print ('#.'*(W//2)+'#')
  else:
   if W % 2 == 0:
    print ('.#'*(W//2))
   else:
    print ('.#'*(W//2)+'.')
 print ''