Minimum Expression
时间限制:C/C++/Rust/Pascal 2秒,其他语言4秒
空间限制:C/C++/Rust/Pascal 256 M,其他语言512 M
64bit IO Format: %lld

题目描述

You are given an integer of length n consisting digits 1 to 9. There is no digit 0 in the integer.

Now, you need to insert m () plus signs into the integer to form an expression. You can choose to insert the plus signs anywhere between the digits, but no two plus signs can be adjacent in the final expression. The plus signs also cannot be at the beginning or the end of the expression.

Output the value of the minimum possible expression.

输入描述:

The first line contains two integers, n and m ().

The second line contains a number of n digits.

输出描述:

Output one number, the answer.
示例1

输入

复制
3 1
919

输出

复制
28