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#include<bits/stdc++.h>
using namespace std;
int sum(int a, int b, vector<int>&v)
{
    if(a>b)
        return 0;
    return(v[b]-v[a-1]);
}
int main()
{
    ios_base::sync_with_stdio(0);
    cout.tie(0);
    cin.tie(0);
    int n, k, t;
    cin>>n>>k>>t;
    vector<int>v(n+1), prefonline(n+1), pref(n+1), prefnormal(n+1);
    pref[0]=0;
    prefnormal[0]=0;
    prefonline[0]=0;
    char c;
    for(int i=1; i<=n; i++)
    {
        cin>>c;
        v[i]=(int)c-(int)'0';
        pref[i]=pref[i-1];
        prefnormal[i]=prefnormal[i-1];
        prefonline[i]=prefonline[i-1];
        if(v[i]!=3)
            pref[i]++;
        if(v[i]==2)
            prefonline[i]++;
        else if(v[i]==1)
            prefnormal[i]++;
    }
    if(k>=pref[n])
        cout<<n;
    else if(pref[n]-prefonline[n]<=k)
    {
        int icanmiss=k-prefnormal[n];
        cout<<n-prefonline[n]+min(icanmiss, prefonline[n]);

    }
    else
    {
        int res=-1;
        for(int i=t+1; i<=n-t; i++)
        {
            for(int j=i; j<=n-t; j++)
            {
                //cout<<i<<" "<<j<<" "<<res<<endl;
                int miss=sum(1, i-t-1, prefnormal)+sum(j+t+1, n, prefnormal)+sum(i-t, i-1, pref)+sum(j+1, j+t, pref);
                if(miss<=k)
                {
                    res=max(res, n-(2*t+j-i+1)-sum(1, i-t-1, prefonline)-sum(j+t+1, n, prefonline)+min(k-miss, sum(1, i-t-1, prefonline)+sum(j+t+1, n, prefonline)));
                    //if(res==7)
                    //    cout<<i<<" "<<j<<" "<<sum(1, i-t-1, prefonline)<<" "<<sum(j+t+1, n, prefonline)<<" "<<k-miss<<endl;
                }
            }
        }
        cout<<res;
    }
}