#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
const int K = 10;
int n, m, k, sum[N];
char str[N];
int f[N][K][2];
int calc(int l, int r) { return sum[r] - sum[l - 1]; }
bool check(int mid)
{
	memset(f, 0x3f, sizeof(f)); f[0][0][0] = 0;
	for (int i = 1; i <= n; i++)
	for (int j = 0; j <= k; j++)
	{
		f[i][j][0] = min(f[i - 1][j][0], f[i - 1][j][1]);
		if (!j || i < mid) continue;
		f[i][j][1] = min(f[i][j][1], f[i - mid][j - 1][0] + calc(i - mid + 1, i));
	}
	return min(f[n][k][0], f[n][k][1]) <= m;
}
int main()
{
	scanf("%d%d%d", &n, &m, &k);
	scanf("%s", str + 1);
	for (int i = 1; i <= n; i++) sum[i] = sum[i - 1] + (str[i] == '0');
	int l = 1, r = n, mid, ans = -1;
	while (l <= r)
	{
		mid = (l + r) >> 1;
		if (check(mid)) { ans = mid; l = mid + 1; }
		else r = mid - 1;
	}
	printf("%d\n", ans);
	return 0;
}