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#include <bits/stdc++.h>
#pragma GCC target ("avx2,fma")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("unroll-loops")

//#define int long long
#define ll long long
#define ld long double
#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define FOR(i,l,r) for(int i=(l);i<=(r);i++)
#define ROF(i,r,l) for(int i=(r);i>=(l);i--)
using namespace std;
ll infl=1000000000000000007;
int inf=1000000007;
int mod=998244353;
int mod1=998244353;

#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif

const int N=8007;

int pref1[N];
int pref2[N];
int pref3[N];
int suf1[N];
int suf2[N];
int suf3[N];

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n,k,l,ans=-1;
    cin>>n>>k>>l;
    string s;
    cin>>s;
    FOR(i,1,n)
    {
		pref1[i]=pref1[i-1];
		pref2[i]=pref2[i-1];
		pref3[i]=pref3[i-1];
		if(s[i-1]=='1') pref1[i]++;
		if(s[i-1]=='2') pref2[i]++;
		if(s[i-1]=='3') pref3[i]++;
	}
	ROF(i,n,1)
	{
		suf1[i]=suf1[i+1];
		suf2[i]=suf2[i+1];
		suf3[i]=suf3[i+1];
		if(s[i-1]=='1') suf1[i]++;
		if(s[i-1]=='2') suf2[i]++;
		if(s[i-1]=='3') suf3[i]++;
	}
	int K=k-pref1[n];
	if(K>=0) ans=pref3[n]+pref1[n]+min(K,pref2[n]);
	FOR(i,1,n)
	{
		FOR(j,i+l,n-l+1)
		{
			K=k-pref1[i+l-1]-suf1[j]-(pref2[i+l-1]-pref2[i-1])-(suf2[j]-suf2[j+l]);
			if(K<0) continue;
			ans=max(ans,pref3[i-1]+suf3[j+l]+pref1[i-1]+suf1[j+l]+min(K,pref2[i-1]+suf2[j+l]));
			debug(i,j,K,ans,pref3[i-1]+suf3[j+l]+pref1[i-1]+suf1[j+l]);
		}
	} 
	cout<<ans<<endl;
    
    return 0;
}