while True:

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

    if x == 0 and y == 0:

        break



    if x > y:

        z = x

        x = y

        y = z



    print((x, y))



while True:

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

    if x == 0 and y == 0:

        break



    if x > y:

        x, y = y, x



    print((x, y))



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

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

-        z = x -        x = y -        y = z +        x, y = y, x