Minimal string

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

inputFormat

Input

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

outputFormat

Output

Print resulting string u.

Examples

Input

cab

Output

abc

Input

acdb

Output

abdc

样例

cab

abc

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