#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned long long
#define pll pair<ll, ll>
const int N = 3e5 + 50;
const int mod = 998244353;

ll dp[N][10][2], n, m, k, res[N];
ll s[N], ans = -1;
char s0;

void solve()
{
    cin >> n >> m >> k;
    for (int i = 1; i <= n; i++)
    {
        cin >> s0;
        s[i] = s0 - '0';
        if (s[i] == 0) res[i] = res[i - 1] + 1;
        else res[i] = res[i - 1];
    }
    ll l = 1, r = n, mid;
    while (l <= r)
    {
        mid = l + r >> 1;
        for (int i = 0; i <= n; i++)
        {
            for (int j = 1; j <= k; j++)
            {
                dp[i][j][0] = dp[i][j][1] = 1e18;
            }
        }
        for (int i = 1; i <= n; i++)
        {
            for (int j = 1; j <= k; j++)
            {
                if (s[i] == 0)
                {
                    dp[i][j][0] = min(dp[i][j][0], dp[i - 1][j][0]);
                    dp[i][j][0] = min(dp[i][j][0], dp[i - 1][j][1]);

                    dp[i][j][1] = min(dp[i][j][1], dp[i - 1][j][1] + 1);
                    dp[i][j][1] = min(dp[i][j][1], dp[i - 1][j][0] + 1);
                }
                else
                {
                    dp[i][j][1] = min(dp[i][j][1], dp[i - 1][j][1]);
                    dp[i][j][1] = min(dp[i][j][1], dp[i - 1][j][0]);
                }
                if (i >= mid && j >= 1)
                {
                    dp[i][j][1] = min(dp[i][j][1], dp[i - mid][j - 1][0] + res[i] - res[i - mid]);
                }
            }
        }
        //if (mid == 4) cout << dp[4][1][1];
        if (dp[n][k][0] <= mid || dp[n][k][1] <= mid)
        {
            l = mid + 1;
            ans = max(ans, mid);
            //cout << dp[n][k][0] << ' ' << dp[n][k][1] << '\n';
        }
        else r = mid - 1;
    }
    cout << ans;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    ll T = 1;
    //cin >> T;
    while (T --)
    {
        solve();
    }
    return 0;
}