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

int dp[200003][8][2];

int main()
{
    cin.tie(0)->sync_with_stdio(0);
    int n, m, k;
    string s;
    cin >> n >> m >> k >> s;
    vector<int> cnt_0(n + 1);
    s.insert(0, " ");
    for (int i = 1; i <= n; ++i)
        cnt_0[i] = cnt_0[i - 1] + (s[i] == '0');
    int l = 0, r = 2e5+1;
    auto check = [&](int tar)
    {
        for (int i = 0; i <= n; ++i)
        {
            for (int j = 0; j <= k; ++j)
            {
                if(j==0)
                {
                    dp[i][0][1]=0x3f3f3f3f;
                }
                else
                {
                    dp[i][j][0] = dp[i][j][1] = 0x3f3f3f3f;
                }
            }
        }
        
        for (int i = 1; i <= n; ++i)
        {
            for (int j = 0; j <= k; ++j)
            {
                if (s[i] == '1')
                {
                    dp[i][j][0] = min(dp[i][j][0], dp[i - 1][j][0]);
                    dp[i][j][1] = min(dp[i][j][1], dp[i - 1][j][1]);//实际上是一种泛化的讨论
                }
                else
                {
                    dp[i][j][0] = min({dp[i][j][0], dp[i - 1][j][0], dp[i - 1][j][1]});
                    dp[i][j][1] = min(dp[i][j][1], dp[i - 1][j][1] + 1);
                }

                if (j >= 1 && i >= tar && dp[i - tar][j - 1][0] != 0x3f3f3f3f)
                {
                    dp[i][j][1] = min(dp[i][j][1], dp[i - tar][j - 1][0] + cnt_0[i] - cnt_0[i - tar]);
                }
            }
        }
        // for (int i = 1; i <= n; ++i) {
        //           for (int j = 0; j <= k; ++j) {
        //               cerr << i << ' ' << j << ' ' << 0 << ' ' << dp[i][j][0] << '\n';
        //               cerr << i << ' ' << j << ' ' << 1 << ' ' << dp[i][j][1] << '\n';
        //           }
        //       }
        return min(dp[n][k][0], dp[n][k][1]) <= m;
    };
    // check(3);
    int ans=-1;
    while (l < r)
    {
        int mid = (l + r ) >> 1;
        // cerr << l << ' ' << r << ' ' << mid << '\n';
        if (check(mid))
        {
            ans=mid;
            l = mid+1;
        }
        else
        {
            r = mid;
        }
    }
    cout<<ans;
    return 0;
}