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

#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2")

#define LL long long
#define int long long

int32_t main() {

    int n,k,t;
    cin>>n>>k>>t;
    vector<char> tab(n);
    vector<int> prefix1(n, -1);
    vector<int> prefix2(n, -1);
    vector<int> prefix3(n, -1);
    int s3=0;
    int s1 = 0;
    int s2 = 0;
    for(int i=0;i<n;i++){
        cin>>tab[i];
        tab[i] -= '0';
        if(tab[i] == 1){
            s1++;
        }
        if(tab[i] == 2){
            s2++;
        }
        if(tab[i] == 3){
            s3++;
        }
    }
    prefix1[0] = 0;
    prefix2[0] = 0;
    prefix3[0] = 0;
    for(int i=1;i<n;i++){
        prefix1[i] = prefix1[i-1] + (tab[i-1] == 1? 1:0);
        prefix2[i] = prefix2[i-1] + (tab[i-1] == 2? 1:0);
        prefix3[i] = prefix3[i-1] + (tab[i-1] == 3? 1:0);
    }

    int m = -1;
    
    if(s1 <= k){
        cout<<n-max(0ll, s1+s2-k)<<endl;
        return 0;
    }

    for(int i=0;i<n-2*t+1;i++){
        for(int j=i+t;j<n-t+1;j++){
            int stracone = 0;
            stracone += prefix1[i+t];
            stracone += s1 - prefix1[j];
            stracone += prefix2[i+t] - prefix2[i];
            stracone += (j+t>=n?s2:prefix2[j+t]) - prefix2[j];
            if(stracone > k) continue;

            int pozostalo = k - stracone;
            int wolne = 0;
            int zdalne = 0;
            wolne += prefix3[i];
            wolne += s3 - (j+t>=n?s3:prefix3[j+t]);
            wolne += prefix1[i];
            wolne += s1 - (j+t>=n?s1:prefix1[j+t]);

            zdalne += prefix2[i];
            zdalne += s2 - (j+t>=n?s2:prefix2[j+t]);

            int wyn = wolne + min(pozostalo, zdalne);

            m = max(m, wyn);
        }
    }
    cout<<m<<endl;

    return 0;
}