#include <bits/stdc++.h>
using namespace std;

int n, M, k;
const int N = 2e5 + 5;
char s[N];
int sum[N];
int f[N][6];
const int inf = 1e9;
int pre[N];
bool check(int x) {
    for (int i = 0; i < n; i++) for (int j = 1; j <= k; j++) f[i][j] = inf;
    for (int i = x + 1; i < n; i++) {
        int ii = pre[i - x - 1];
        if (i == ii + 1) continue; 
        if (s[i] == '0') {
            int cost = sum[i] - sum[ii + 1];
            for (int j = 1; j <= k; j++) {
                f[i][j] = min(f[i][j], f[ii][j - 1] + cost);
            }
        }
    }
    int mn = inf;
    for (int i = 0; i < n; i++) mn = min(mn, f[i][k]);
    return mn <= M;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> n >> M >> k;
    s[0] = '0';
    for (int i = 1; i <= n; i++) cin >> s[i];
    s[n + 1] = '0';
    n += 2;
    for (int i = 0; i < n; i++) {
        if (s[i] == '0') {
            pre[i] = i;
        } else {
            pre[i] = pre[i - 1];
        }
    }
    for (int i = 0; i < n; i++) sum[i + 1] = sum[i] + (s[i] == '0');
    int l = -1, r = n + 1;
    while (r - l > 1) {
        int m = (l + r) / 2;
        if (check(m)) {
            l = m;
        } else {
            r = m;
        }
    }
    cout << l << "\n";
}