#include <iostream>
#include <vector>

using namespace std;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N, W;
    cin >> N >> W;

    vector<int> X(N);
    int max_x = 0;
    for (int i = 0; i < N; ++i) {
        cin >> X[i];
        if (X[i] > max_x) max_x = X[i];
    }

    vector<long long> sum_exact(max_x + 1, 0);
    for (int i = 0; i < N; ++i) {
        long long y;
        cin >> y;
        sum_exact[X[i]] += y;
    }

    long long ans = 0;
    for (int d = W; d <= max_x; ++d) {
        long long cur = 0;
        for (int multiple = d; multiple <= max_x; multiple += d) {
            cur += sum_exact[multiple];
        }
        if (cur > ans) ans = cur;
    }

    cout << ans << '\n';
    return 0;
}