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

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

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

    const int MAXX = 200000;
    vector<int> X(N);
    vector<long long> Y(N);
    for (int i = 0; i < N; ++i) cin >> X[i];
    for (int i = 0; i < N; ++i) cin >> Y[i];

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

    long long ans = 0;
    for (int g = W; g <= MAXX; ++g) {
        long long cur = 0;
        for (int m = g; m <= MAXX; m += g) {
            cur += sum_exact[m];
        }
        ans = max(ans, cur);
    }

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