#include <bits/stdc++.h>
using namespace std;
int n, m, k;
int pre[200005];
string s;
int dp[200005][6][2];
bool check(int x)
{
    for (int i = 0; i <= n; ++i)
        for (int j = 0; j <= k; ++j)
            dp[i][j][0] = dp[i][j][1] = 0x3f3f3f3f;
    dp[0][0][0] = 0;
    for (int i = 1; i <= n; ++i) {
        for (int j = 0; j <= k; ++j) {
                dp[i][j][0] = min(dp[i - 1][j][0], dp[i - 1][j][1]);
                dp[i][j][1] = min(dp[i][j][1], dp[i - 1][j][1]);
                if(j!=0&&i>=x)dp[i][j][1] = min(dp[i][j][1], dp[i - x][j - 1][0] + (pre[i] - pre[i - x]));
        }
    }
    return min(dp[n][k][0], dp[n][k][1]) <= m;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m >> k;
    cin >> s;
    for (int i = 1; i <= n; ++i) {
        pre[i] = pre[i - 1] + (s[i - 1] == '0');
    }
    int l = 1, r = n, ans = -1;
    while (l <= r) {
        int mid = (l + r) >> 1;
        if (check(mid))
            ans = mid, l = mid + 1;
        else
            r = mid - 1;
    }
    cout << ans << '\n';
}