Problem1456--Minimal string

1456: Minimal string

Time Limit: 2 Sec  Memory Limit: 256 MB
Submit: 0  Solved: 0
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Description

time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Petya recieved a gift of a string s with length up to 105 characters for his birthday. He took two more empty strings t and u and decided to play a game. This game has two possible moves:

  • Extract the first character of s and append t with this character.
  • Extract the last character of t and append u with this character.

Petya wants to get strings s and t empty and string u lexicographically minimal.

You should write a program that will help Petya win the game.

Input

First line contains non-empty string s (1≤|s|≤105), consisting of lowercase English letters.

Output

Print resulting string u.

Examples
Input
cab
Output
abc
Input
acdb
Output
abdc

Source/Category

 
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