Problem:
Swapping Two Numbers

Write a program which reads two integers x and y, and prints them in ascending order.

Input

The input consists of multiple datasets. Each dataset consists of two integers x and y separated by a single space.

The input ends with two 0 (when both x and y are zero). Your program should not process for these terminal symbols.

Output

For each dataset, print x and y in ascending order in a line. Put a single space between x and y.

Constraints

0 ≤ x, y ≤ 10000

the number of datasets ≤ 3000

Sample Input

3 2
2 2
5 3
0 0

Sample Output

2 3
2 2
3 5

Solution in Python3 (judge verdict: Accepted)

ls = []
while True:
    x,y = map(int,input().split())
    if x == y == 0:
        break
    if x > y :
        tmp = y
        y = x
        x = tmp
    ls.append([x,y])

for i in range(len(ls)):
    print("{} {}".format(ls[i][0],ls[i][1]))