#include <bits/stdc++.h>
using namespace std;
using ll=long long;
const int inf=1e8+7;
const int N=2e5+5;
const int K=7;
int n,m,k;
char s[N];
int dp[N][K],minn[N][K];
int cnt[N][2],pre[N];
int check(int mid){
    for(int i=0;i<=n;i++)
        for(int j=0;j<=k;j++){
            dp[i][j]=inf;
            minn[i][j]=inf;
        }
    for(int i=0;i<=n;i++) dp[i][0]=minn[i][0]=0;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=k;j++){
            if(i>=mid){
                dp[i][j]=cnt[i][0]-cnt[i-mid][0]+minn[pre[i-mid]][j-1];
            }
            minn[i][j]=min(dp[i][j],minn[i-1][j]);
        }
    }
    int ans=inf;
    for(int i=1;i<=n;i++) ans=min(ans,dp[i][k]);
    return ans<=m;
}
int binary(){
    int l=1,r=n,mid;
    int ans=-1;
    while(l<=r){
        mid=(l+r)>>1;
        if(check(mid)){
            l=mid+1;
            ans=mid;
        }else r=mid-1;
    }
    return ans;
}
void solve(){
    cin>>n>>m>>k;
    cin>>s+1;
    for(int i=1;i<=n;i++){
        int d=s[i]-'0';
        cnt[i][d]++;
        if(d==1) pre[i]=i;
        if(s[i]=='0') continue;
        if(i>1&&s[i-1]=='1') pre[i]=pre[i-1];
    }
    for(int i=1;i<=n;i++){
        cnt[i][0]+=cnt[i-1][0];
        cnt[i][1]+=cnt[i-1][1];
        if(pre[i]==0) pre[i]=i;
        else pre[i]=pre[i]-1;
    }
    int ans=binary();
    cout<<ans<<"\n";
}
int main(){
    ios::sync_with_stdio(false),cin.tie(0);
    int _=1;
    // cin>>_;
    while(_--)  solve();
    return 0;
}