For the resulting tree, print a list of all leaves (vertices that have no children) in ascending order.
Input
Enter a sequence of integers ending in zero. Zero itself is not included in the sequence.
Output
Print the answer to the problem.
 
Examples
| # | 
Input | 
Output | 
| 1 | 
7 3 2 1 9 5 4 6 8 0
 
 | 
1
4
6
8
 
 |