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

#define rep(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rrep(i, a, b) for (int i = (int)(a); i > (int)(b); i--)
#define ll long long
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define PQ priority_queue<int, vector<int>, greater<int>>
#define PQ_g priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>>
#define chmin(a, b) a = min(a, b)
#define chmax(a, b) a = max(a, b)
const int d4[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
const int d8[8][2] = {{0, 1}, {1, 1}, {1, 0}, {1, -1}, {0, -1}, {-1, -1}, {-1, 0}, {-1, 1}};
void Yes(bool b) {cout << (b ? "Yes" : "No") << endl;}

int main() {
    int n, w; cin >> n >> w;
    vector<vector<ll>> goods(200001, vector<ll>(0));
    vector<int> x(n);
    vector<ll> y(n);
    rep(i, 0, n) cin >> x[i];
    rep(i, 0, n) cin >> y[i];
    rep(i, 0, n) {
        goods[x[i]].push_back(y[i]);
    }

    ll ans = 0LL;

    rep(d, w, 200001) {
        vector<ll> d_goods;
        for (int i = 0; i <= 200000; i += d) {
            for (auto &g: goods[i]) d_goods.push_back(g);
        }
        ll sum = 0LL;
        for (auto &g: d_goods) sum += g;
        ans = max(ans, sum);
    }

    cout << ans << endl;
}