#include <bits/stdc++.h>
#define int long long
#define endl '\n'

using namespace std;

const int N=2e5+5;

int n,m,k,f[N][6],b[N];
string s;

bool judge(int x)
{
	memset(f,0x3f,sizeof f);
	f[0][0]=0;
	for(int i=x;i<=n;i++)
	{
		for(int j=1;j<=k;j++) f[i][j]=f[i-1][j];
		for(int j=1;j<=k;j++)
		{
//			if(i<(x+1)*j-1) continue;
			if(s[i-x]=='1') continue;//if(i==8&&x==3)cout<<"*";
			if(i==x)
				f[i][j]=min(f[i-x][j-1]+b[i]-b[i-x],f[i][j]);
			else if(i-x-1>=0)
			{
				
				f[i][j]=min(f[i-x-1][j-1]+b[i]-b[i-x],f[i][j]);
			}
				
		}
	}
	
	return f[n][k]<=m;
}

void solve()
{
	cin>>n>>m>>k>>s;
	s="0"+s;
	int l=1,r=n,mid,ans=-1;
	for(int i=1;i<=n;i++) b[i]=b[i-1]+(s[i]=='0');
//	for(int i=1;i<=n;i++) cout<<b[i]<<" ";cout<<endl;
	while(l<=r)
	{
		mid=(l+r)/2;
		if(judge(mid)) l=mid+1,ans=max(ans,mid);
		else r=mid-1;
	}
	
//	judge(3);
//	for(int i=0;i<=n;i++)
//	{
//		for(int j=0;j<=k;j++) cout<<f[i][j]<<" ";
//		cout<<endl;
//	}
	
	cout<<ans<<endl;
}

signed main()
{
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	int T=1;
	//	cin>>T;
	while(T--) solve();
	return 0;
}