Олимпиадный тренинг

Задача 44647. Bring out the leaves


Задача

Темы: Деревья

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