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#include <bits/stdc++.h>
using namespace std;
const int maxn = 8007;

int n,k,t;
int arr[maxn];
// 0 - office meeting, 1 - remote meeting
int meetingsPrefix[2][maxn];

int main() {
    cin >> n >> k >> t;
    for (int i = 0; i<n; i++) {
        char c; cin >> c;
        arr[i] = c-'0';
        if (i!=0) {
            meetingsPrefix[0][i] = meetingsPrefix[0][i-1];
            meetingsPrefix[1][i] = meetingsPrefix[1][i-1];
        }
        if(arr[i]!=3) {
            if(i==0) {
                meetingsPrefix[arr[i]-1][i] = 1;
                meetingsPrefix[1-(arr[i]-1)][i] = 0;
            }
            else {
                meetingsPrefix[arr[i]-1][i] = 1 + meetingsPrefix[arr[i]-1][i-1];
                meetingsPrefix[1-(arr[i]-1)][i] = meetingsPrefix[1-(arr[i]-1)][i-1];
            }
        }
    }
    int totalMeetings = meetingsPrefix[0][n-1] + meetingsPrefix[1][n-1];
    int officeMeetings = meetingsPrefix[0][n-1];
    int remoteMeetings = meetingsPrefix[1][n-1];

    // moge pominac wszystkie
    if (k >= totalMeetings) {
        cout << n << "\n";
        return 0;
    }

    // nie musze jechac do biura jezeli moge pominac wszystkie biurowe spotkania
    if (k >= officeMeetings) {
        // i wtedy nie jedziemy do biura, ale musimy pojsc na tyle spotkan
        // ze pomijamy wszystkie w biurze i "iles" zdalnych
        cout << n - (totalMeetings - k) << "\n";
        return 0;
    }

    // nic nie zadzialalo? to musimy sprawdzic
    // wszystkie kombinacje wyjazdow do biura w O(n^2)
    int start = 0;
    int end = t;
    int maxTasksSoFar=-1;
    while (start + 2*t <= n) {
        while (end + t <= n) {
            // cout << "Rozpatrujemy zakres " << start << " i " << end << "\n";
            // 1. wezmy wszystkie spotkania jak jestesmy w biurze bo czemu by nie
            int takenOfficeMeetings =
                (meetingsPrefix[0][end-1] - meetingsPrefix[0][start+t-1]) +
                (meetingsPrefix[1][end-1] - meetingsPrefix[1][start+t-1]);
            // cout << ">Wziete spotkania biurowe " << takenOfficeMeetings << "\n";

            int possibleRemoteMeetingsLeft = meetingsPrefix[1][max(0,start-1)];
            // cout << ">Lewe spotkania zdalne " << possibleRemoteMeetingsLeft << "\n";

            int possibleRemoteMeetingsRight = meetingsPrefix[1][n-1] - meetingsPrefix[1][min(n-1, end+t-1)];
            // cout << ">Prawe spotkania zdalne " << possibleRemoteMeetingsRight << "\n";

            int possibleRemoteMeetings = possibleRemoteMeetingsLeft + possibleRemoteMeetingsRight;
            int requiredMeetingsLeft = totalMeetings - k - takenOfficeMeetings;
            // cout << ">Jest " << totalMeetings << " spotkan\n";
            // cout << ">Wzialem juz " << takenOfficeMeetings << " spotkan\n";
            // cout << ">Potrzebne jeszcze " << requiredMeetingsLeft << " spotkan\n";

            if (possibleRemoteMeetings >= requiredMeetingsLeft) {
                int outsideOfficeMeetings = takenOfficeMeetings + requiredMeetingsLeft;
                // cout << "* Udalo sie zrobic " << n-(requiredMeetingsLeft+end-start + t) << " allgosow\n";
                maxTasksSoFar = max(maxTasksSoFar, n-(requiredMeetingsLeft+end-start + t));
            }
            end++;
            // cout << "\n";
        }
        start++;
        end = start+t;
    }

    cout << maxTasksSoFar << "\n";
}