#include<bits/stdc++.h>

#define int long long
using namespace std;
typedef pair<int,int> PII;
const int N = 200010;
char a[N];
int s[N];
int n,m,k;

bool check(int x)
{
    int ans = 1e9;
    int f[N][5][2];
    memset(f,0x3f,sizeof f);
    f[0][0][0] = 0;
    for(int i = 1;i <= n;i++)
    {
        for(int j = 1;j <= k;j++)
        {
            f[i][j][0] = min(f[i - 1][j][0],f[i - 1][j][1]);
            if(i >= x && a[i - x] == '0') f[i][j][1] = f[i - x][j - 1][0] + s[i] - s[i - x];
            if(j == k) ans = min({ans,f[i][k][0],f[i][k][1]});
        }
    }
    return ans <= m;
}

void solve()
{
    
    cin >> n >> m >> k;
    cin >> a + 1;
    a[0] = '0';
    for(int i = 1;i <= n;i++) 
    {
        s[i] = s[i - 1];
        if(a[i] == '0') s[i]++;
    }
    
   
    
    int l = 0, r = n;
    while(l < r)
    {
        int mid = l + r + 1 >> 1;
        if(check(mid)) l = mid;
        else r = mid - 1;
    }
    if(l == 0) l--;
    cout << l << endl;
    
    
}



signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    
    int T = 1;
    //cin >> T;

    while(T--)
    {
        solve();
    }
    return 0;
}