Digit Deletion

Problem Description

A high-precision positive integer $n$ (at most $250$ digits) is entered from the keyboard. After deleting any $k$ of its digits, the remaining digits, in their original left-to-right order, form a new non-negative integer. For the given $n$ and $k$, find a scheme that makes the new number formed by the remaining digits as small as possible.

Input Format

Two lines of positive integers.

The first line is the high-precision positive integer $n$.

The second line is a positive integer $k$, the number of digits to delete.

Output Format

One integer: the smallest remaining number.

Sample Input

175438
4

Sample Output

13

Constraints

Let $\operatorname{len}(n)$ denote the number of digits of $n$. It is guaranteed that $1 \le k < \operatorname{len}(n) \le 250$.