Minimal string

Petya recieved a gift of a string s with length up to10⁵ characters for his birthday. He took two more empty stringst 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 lexigraphically 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.

Example

Input

cab

Output

abc

Input

acdb

Output

abdc

题意：给你3个字符串s,t,u. 有两种操作：1.可以取s的第一个字符串加在t后 2.可以吧t的最后一个字符加在u后,使u的字典序最小

题解：逆向维护一个minn数组，表示每个字符从它开始的最小的字符，s字符不断入栈，如果栈顶<=minn[i],则输出栈顶

#include
#include
#include
#include
#include
#include
#define CL(a) memset(a,0,sizeof(a))
using namespace std;
const int maxn = 1e5 +10;
char str[maxn];
char minn[maxn];
int main()
{
    cin>>str;
    int len=strlen(str);
    minn[len-1]=str[len-1];
    for(int i=len-1;i>=0;i--){
        if(str[i-1] < minn[i])
            minn[i-1] = str[i-1];
        else
            minn[i-1] = minn[i];
    }
    stack Q;
    int k=0;
    for(int i=0;i