Solve in Python:
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 $10^x$.


-----Input-----

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.


-----Output-----

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 $10^x$.


-----Examples-----
Input
11 5 2
11010100101

Output
1

Input
11 5 1
11010100101

Output
3



-----Note-----

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 $100000$.
n,x,y=[int(x) for x in input().split()]
a=[int(x) for x in list(input())]
counter=0
for i in range(n-x,n):
    if i==n-y-1:
        if a[i]==0:
            counter+=1
    else:
        if a[i]==1:
            counter+=1
print(counter)