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

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

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

    vector<int> X(N);
    vector<long long> Y(N);

    int MX = 0;
    for (int i = 0; i < N; i++) {
        cin >> X[i];
        MX = max(MX, X[i]);
    }
    for (int i = 0; i < N; i++) {
        cin >> Y[i];
    }

    vector<long long> by_weight(MX + 1, 0);
    for (int i = 0; i < N; i++) {
        by_weight[X[i]] += Y[i];
    }

    long long ans = 0;
    for (int g = W; g <= MX; g++) {
        long long cur = 0;
        for (int multiple = g; multiple <= MX; multiple += g) {
            cur += by_weight[multiple];
        }
        ans = max(ans, cur);
    }

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