CF1165A.Remainder

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 $0 \le y \lt x \lt n$. 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 $10^x$.

你得到一个由 $n$ 位数字组成的巨大十进制数。保证该数没有前导零。该数的每一位数字均为 $0$ 或 $1$。

你可以对该数执行若干次（可能为零次）操作。每次操作中，你可以将该数的任意一位数字进行更改：即将 $0$ 改为 $1$，或将 $1$ 改为 $0$。某些操作后，你可能得到带有前导零的数，但这对本题无影响。

你还给定两个整数 $0 \le y \lt x \lt n$。你的任务是计算为使该数对 $10^x$ 取模后余数恰好为 $10^y$ 所需执行的最少操作次数。换言之，所得数除以 $10^x$ 的余数应为 $10^y$。

The first line of the input contains three integers $n, x, y$ ($0 \le y \lt x \lt n \le 2 \cdot 10^5$) — 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.

输入的第一行包含三个整数 $n, x, y$（$0 \le y \lt x \lt n \le 2 \cdot 10^5$），分别表示该数字的长度以及整数 $x$ 和 $y$。

输入的第二行包含一个由 $n$ 位十进制数字组成的数字，该数字的每一位均为 0 或 1。保证该数字的首位为 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 $10^x$.

输出一个整数——为得到模 $10^x$ 余 $10^y$ 的数所需执行的最少操作次数。换句话说，所得数除以 $10^x$ 的余数应为 $10^y$。

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 $100000$.

在第一个例子中，执行一次操作后，该数将变为 $11010100100$，它对 $100000$ 取模的余数为 $100$。

在第二个例子中，执行三次操作后，该数将变为 $11010100010$，它对 $100000$ 取模的余数为 $10$。