Remainder

## 题目描述 Aiming_High神仙给你一个由$n$位数字组成的数，且保证这个数字没有前导零，且每一位数字要么是$0$要么是$1$。 Aiming_High神仙需要你对这个数进行若干次操作（可能是$0$次）。每次操作中，你可以更改其中的任何数位，把这个数位上的数字从$1$变成$0$或从$0$变成$1$。操作后的数可能带有前导零，但并不影响这个问题。 Aiming_High神仙还给了你两个数字$x$，$y$。你要做的是最小化操作次数，使得操作后的数除以$10^x$的余数等于$10^y$。 ## 输入输出格式 ### 输入格式： 输入的第一行包含三个整数$n$，$x$，$y$。 第二行包括一个数，由$n$个数位组成。保证每个数位上的数都是$0$或$1$，且无前导零。 ### 输出格式： 输出一个整数，表示最小操作次数。

You are given a huge decimal number consisting of $ n $ digits. It is guaranteed that this number has no leading zeros. Each digit of this number is either 0 or 1. You may perform several (possibly zero) operations with this number. During each operation you are allowed to change any digit of your number; you may change 0 to 1 or 1 to 0. It is possible that after some operation you can obtain a number with leading zeroes, but it does not matter for this problem. You are also given two integers $ 0 \le y < x < n $ . Your task is to calculate the minimum number of operations you should perform to obtain the number that has remainder $ 10^y $ modulo $ 10^x $ . In other words, the obtained number should have remainder $ 10^y $ when divided by $ 10^x $ .

The first line of the input contains three integers $ n, x, y $ ( $ 0 \le y < x < n \le 2 \cdot 10^5 $ ) — the length of the number and the integers $ x $ and $ y $ , respectively. The second line of the input contains one decimal number consisting of $ n $ digits, each digit of this number is either 0 or 1. It is guaranteed that the first digit of the number is 1.

Print one integer — the minimum number of operations you should perform to obtain the number having remainder $ 10^y $ modulo $ 10^x $ . In other words, the obtained number should have remainder $ 10^y $ when divided by $ 10^x $ .

11 5 2
11010100101

1

11 5 1
11010100101

3

In the first example the number will be $ 11010100100 $ after performing one operation. It has remainder $ 100 $ modulo $ 100000 $ . In the second example the number will be $ 11010100010 $ after performing three operations. It has remainder $ 10 $ modulo $ 100000 $ .