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#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
using namespace std;

inline int rangeSum(const vector<int>& pref, int l, int r) {
    if(l > r) return 0;
    return pref[r] - pref[l-1];
}
 
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
 
    int n, k, t;
    cin >> n >> k >> t;
    string s;
    cin >> s;
    s = " " + s;
 
    vector<int> p1(n+1, 0), p2(n+1, 0), p3(n+1, 0), pMeet(n+1, 0);
    for (int i = 1; i <= n; i++){
        p1[i] = p1[i-1] + (s[i]=='1');
        p2[i] = p2[i-1] + (s[i]=='2');
        p3[i] = p3[i-1] + (s[i]=='3');
        pMeet[i] = pMeet[i-1] + ((s[i]=='1' || s[i]=='2') ? 1 : 0);
    }
 
    int total1 = rangeSum(p1, 1, n);
    int total2 = rangeSum(p2, 1, n);
    int total3 = rangeSum(p3, 1, n);
    long long best = -1;

    if(total1 <= k) {
        long long tasksNoTrip = total3 + total1 + min(total2, k - total1);
        best = max(best, tasksNoTrip);
    }

    for (int a = 1; a <= n - t + 1; a++){
        int transitFrom = rangeSum(pMeet, a, a+t-1);
 
        for (int b = a + t; b <= n - t; b++){
            int transitBack = rangeSum(pMeet, b+1, b+t);
            int transitPenalty = transitFrom + transitBack;
            if(transitPenalty > k) continue;
 
            int home_left_1 = rangeSum(p1, 1, a-1);
            int home_left_2 = rangeSum(p2, 1, a-1);
            int home_left_3 = rangeSum(p3, 1, a-1);
            int home_right_1 = rangeSum(p1, b+t+1, n);
            int home_right_2 = rangeSum(p2, b+t+1, n);
            int home_right_3 = rangeSum(p3, b+t+1, n);
 
            int home1 = home_left_1 + home_right_1;
            int home2 = home_left_2 + home_right_2;
            int home3 = home_left_3 + home_right_3;
            int r = k - transitPenalty;
            if(home1 > r) continue;
            long long tasksHome = (long long)home3 + home1 +
                                  min(home2, r - home1);
            best = max(best, tasksHome);
        }
    }
 
    cout << best << "\n";
    return 0;
}


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