F

#include<iostream>
using namespace std;
typedef long long ll;

int main()
{
    int n, k;
    cin >> n >> k;
    int* arr=new int[n];
    int* val=new int[n];
    for (int i = 0; i < n; i++)
    {
        cin >> val[i];

    }
    for (int i = 0; i < n; i++)
    {
        cin >> arr[i];
    }
    int i = 0;
    int j = 0;
    int sum = 0;
    int maxi = 0;
    int ind;
    int temp = INT_MIN;
    while (j < k)
    {
        if (arr[j] == 1)sum = sum + val[j];
        else maxi = maxi + val[j];
        j++;
    }
    temp = max(temp, maxi);
    while (j < n)
    {
        if (arr[j] == 1)sum = sum + val[j];

        else {
            maxi = maxi + val[j];
        }
        if (arr[i] == 0)
        {
            maxi = maxi - val[i];
        }


        i++;
        j++;
        temp = max(maxi, temp);
    }

    cout << temp + sum << endl;
}