### ** blanko**

## Problem Description

Rar the Cat is trying out his new correction tape. He takes a sheet of paper, containing an *N*-digit integer, and decides to remove *K* of these digits. The remaining digits will join together to form a new integer with *N* - *K* digits.

Help Rar find the minimum possible integer he can form. Note that the resultant integer *cannot have leading zeroes*.

## Input

The first line of input will contain two integers, *N* and *K*.

The second line of input will contain one integer, representing the original integer Rar has.

## Output

Output a single line containing one integer, the minimum possible resultant integer Rar can form.

## Limits

1 ≤ K < N.

Subtask 1 (8%): 2 ≤ N ≤ 16.

Subtask 2 (12%): 2 ≤ N ≤ 2 000. Each digit in the integer will be a 0 or a 1.

Subtask 3 (14%): 2 ≤ N ≤ 2 000.

Subtask 4 (6%): 2 ≤ N ≤ 100 000. K = N - 1.

Subtask 5 (16%): 2 ≤ N ≤ 100 000. Each digit in the integer will be a 0 or a 1.

Subtask 6 (18%): 2 ≤ N ≤ 100 000. No digit in the original integer will be a 0.

Subtask 7 (15%): 2 ≤ N ≤ 100 000.

Subtask 8 (11%): 2 ≤ N ≤ 5 000 000.

Subtask 9 (0%): Sample Testcases

## Sample Testcase 1

### Input

5 3
23195

### Output

15

## Sample Testcase 2

### Input

10 6
9031193452

### Output

1132

## Sample Testcase 3

### Input

5 2
10101

### Output

100