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)

lists=[]
while True:
    a,b=map(int,input().split())
    if a==0 and b==0:
        break
    if a>b:
        lists.append(b)
        lists.append(a)
    else:
        lists.append(a)
        lists.append(b)

j=0

for i in lists:
    print("{0} {1}".format(lists[2*j],lists[2*j+1]))
    j=j+1
    if j==len(lists)//2:
        break