#include <bits/stdc++.h>
using namespace std;

int main() {
    cin.tie(0)->sync_with_stdio(0);

    int n, w;
    if (!(cin >> n >> w)) return 0;

    vector<int> x(n);
    for (int i = 0; i < n; ++i) cin >> x[i];

    vector<long long> y(n);
    for (int i = 0; i < n; ++i) cin >> y[i];

    int max_x = 0;
    for (int i = 0; i < n; ++i) {
        max_x = max(max_x, x[i]);
    }

    if (w > max_x) {
        cout << 0 << '\n';
        return 0;
    }

    vector<long long> sum_y(max_x + 1, 0);
    for (int i = 0; i < n; ++i) {
        sum_y[x[i]] += y[i];
    }

    long long ans = 0;
    for (int d = w; d <= max_x; ++d) {
        long long current_sum = 0;
        for (int k = d; k <= max_x; k += d) {
            current_sum += sum_y[k];
        }
        ans = max(ans, current_sum);
    }

    cout << ans << '\n';

    return 0;
}