#include <bits/stdc++.h>   using namespace std;   long long M = 1000000007;   int main() {     int n, x, y;     cin >> n >> x >> y;     string s;     cin >> s;     int ans = 0;     for (int i = 0; i < x; i++) {       int pos = n - i - 1;       char current =  0 ;       if (i == y) {         current =  1 ;       }       if (current != s[pos]) {         ans++;       }     }     cout << ans <<   n ;     return 0;   }   