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