while True:

    a=sorted(map(int,input().split()))

    if a==[0,0]:

        quit()

    print((*a))

while True:

	x,y=sorted(map(int,input().split()))

	if (x==0) and(y==0):

		break

	print((x, y))

while True:
    a = sorted(map(int, input().split()))
    if a == [0, 0]:
        quit()
    print((*a))

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

-    a = sorted(map(int, input().split())) -    if a == [0, 0]: -        quit() -    print((*a)) +    x, y = sorted(map(int, input().split())) +    if (x == 0) and (y == 0): +        break +    print((x, y))