#include <bits/stdc++.h>
using namespace std;
int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
	int n, k, curr=3, t=(cin>>n>>k>>t, t);
	char c; vector<vector<int>> s_pr(n+1, vector<int>(3, 0));
	for(int i=1; i<=n; i++){
		c=(cin>>c, c);
		s_pr[i][c-'1']=s_pr[i-1][c-'1']+1;
		s_pr[i][(c-'1'+1)%3]=s_pr[i-1][(c-'1'+1)%3];
		s_pr[i][(c-'1'+2)%3]=s_pr[i-1][(c-'1'+2)%3];
	}
	if(s_pr[n][0]<=k){
		cout<<s_pr[n][0]+s_pr[n][2]+min(s_pr[n][1],k-s_pr[n][0]);
		return 0;
	}
	int wyn=-1;
	for(int i=t+1; i<=n-t; i++){
		for(int j=i; j<=n-t; j++){
			int s1=s_pr[n][0]-s_pr[j][0]+s_pr[i-1][0], s2=s_pr[i-1][1]-s_pr[i-t-1][1]+s_pr[j+t][1]-s_pr[j][1];
			if(s1+s2<=k){
				int s3=s_pr[n][1]-s_pr[j+t][1]+s_pr[i-t-1][1];
				wyn=max(wyn, n-(j-i+1+t*2)-(s3+min(k-s1-s2, s3)));
			}
		}
	}
	cout<<wyn;
	return 0;
}