#include <bits/stdc++.h>
#define eb emplace_back
#define pb pop_back
#define mt make_tuple
#define mp make_pair
#define fi first
#define se second

using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef tuple<int, int, int> tu;
bool Mbe;

const int N = 2e5 + 200;
int n, m, k, s[N], pr[N], f[N][10];
char c[N];

bool chk(int x) {
	memset(f, 0x3f, sizeof(f));
	f[0][0] = 0;
	for (int i = 1; i <= n; i++) {
		for (int j = 0; j <= k; j++)
			f[i][j] = min(f[i][j], f[i - 1][j]);
		if (i - x - 1 >= 0) {
			for (int j = 1; j <= k; j++) {
				f[i][j] = min(f[i][j], f[i - x - 1][j - 1] + x - (s[i] - s[i - x]));
			}
		}
	}
	return f[n][k] <= m;
}

void solve() {
	cin >> n >> m >> k >> (c + 1);
	for (int i = 1; i <= n; i++)
		s[i] = s[i - 1] + (c[i] - '0');
	// for (int i = 1; i <= n; i++) 
		// pr[i] = (c[i] == '0') ? i : pr[i - 1];
	// cout << chk(3) << '\n';
	int l = 1, r = n / k, res = -1;
	while (l <= r) {
		int mid = (l + r) >> 1;
		if (chk(mid)) res = mid, l = mid + 1;
		else r = mid - 1;
	}
	cout << res << '\n';
}

bool Med;
int main() {
	ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
	cerr << (&Mbe - &Med) / 1048576.0 << " MB\n";
	#ifdef FILE
		freopen("1.in", "r", stdin);s
		freopen("1.out", "w", stdout);
	#endif
	int T = 1;
	// cin >> T;
	while (T--) solve();
	cerr << (int)(1e3 * clock() / CLOCKS_PER_SEC) << " ms\n";
	return 0;
}