Write a program which reads two integers x and y, and prints them in ascending order.
x,y = map(int, input().split())
while (x,y) == (0,0):
 if x < y:
  print(x,y)
 else:
  print(y,x)


while True:
 x,y = map(int, input().split())
 if x==0 and y==0:
  break
 if x <= y:
  print(x,y)
 else:
  print(y,x)

 
