while True:

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

	if x == 0 and y == 0:

		break

	print((x, y))
while True:

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

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

		break

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

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

-    if x == 0 and y == 0: +    if (x, y) == (0, 0):