#P797C. Minimal string

    ID: 3857 Type: RemoteJudge 1000ms 256MiB Tried: 0 Accepted: 0 Difficulty: (None) Uploaded By: Tags>data structuresgreedystrings*1700

Minimal string

No submission language available for this problem.

Description

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.

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

Print resulting string u.

Input

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

Output

Print resulting string u.

Samples

cab

abc

acdb

abdc