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#include <iostream>
#include <vector>

using namespace std;

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    string data;
    int n, k, t;
    cin >> n >> k >> t;
    cin >> data;

    int rm, om;
    rm = om = 0;
    for ( char s : data) {
        if (s == '1') om++;
        else if (s == '2') rm++;
    }

    int tm = om + rm;
    int result;
    if (k >= om ) {
        if ( k >= tm ) {
            result = n;
        }  else {
            result = n - (tm - k);
        }
        cout << result << "\n";
        return 0;
    }

    result = -1;
    int ahm, aom, af;
    ahm = af = 0;

    vector<int> ahmv(n+1), afv(n+1);
    ahmv[n] = afv[n] = 0;
    for ( int i = n - 1; i >= 2*t; --i ) {
        switch (data[i]) {
            case '1':
                af++;
                break;
            case '2':
                ahm++;
                break;
            case '3':
                af++;
                break;
        }
        ahmv[i] = ahm;
        afv[i] = af;
    }

    int miw = 0;
    int mustM = tm - k;
    int lahm = 0;
    int laf = 0;

    for (int i = 0; i <= n - 2 * t; i++) {
        miw = 0;
        for (int j = t + i; j <= n - t; j++ ) {
            ahm = ahmv[j+t] + lahm;
            af = afv[j+t] + laf;
            if (tm - ahm - miw <= k) {
                int tmp = af;
                tmp += mustM <= miw ? ahm : ahm + miw - mustM; 
                result = max(result, tmp);
            }
            switch (data[j]) {
                case '1':
                case '2':
                    miw++;
                    break;
            }
        }
        switch (data[i]) {
            case '1':
                laf++;
                break;
            case '2':
                lahm++;
                break;
            case '3':
                laf++;
                break;

        }
    }
    cout << result << "\n";
    return 0;
}