//#pragma clang diagnostic push
//#pragma ide diagnostic ignored "misc-no-recursion"

#include<bits/stdc++.h>

using namespace std;


int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int n, m, k;
    cin >> n >> m >> k;
    string s;
    cin >> s;
    vector<int> v(n + 1);
    for (int i = 0; i < n; ++i) {
        v[i + 1] = v[i] + (s[i] == '0');
    }
    auto cnt0 = [&](int l, int r) {
        return v[r + 1] - v[l];
    };
    auto check = [&](auto self, int k, int m, int start, int ans) -> bool {
        if (ans == 0)return true;
        for (int i = start; i + ans - 1 < n; ++i) {
            if (m >= cnt0(i, i + ans - 1)) {
                if (k == 1)return true;
                int t = i + ans;
                while (t < n && s[t] == '1')t++;
                t++;
                if (self(self, k - 1, m - cnt0(i, i + ans - 1), t, ans))return true;
            }
        }
        return false;
    };
    auto find = [&]() {
        int l = 0, r = n / k + 1;
        while (l + 1 < r) {
            int mid = (l + r) / 2;
            if (check(check, k, m, 0, mid)) {
                l = mid;
            } else {
                r = mid;
            }
        }
        return l;
    };
//    for (int i = 0; i <= n; ++i) {
//        cout << check(check, k, m, 0, i);
//    }
//    cout << endl;
    int ans = find();
    if (ans == 0)ans--;
    cout << ans << endl;
}

//#pragma clang diagnostic pop