#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;
using ll = long long;

int main() {
    cin.tie(nullptr) -> sync_with_stdio(false);
    
    int n, w;
    cin >> n >> w;
    
    vector<int> x(n), y(n);
    rep(i, n) cin >> x[i];
    rep(i, n) cin >> y[i];
    
    int m = 0;
    rep(i, n) m = max(m, x[i]);
    
    vector<ll> s(m+1);
    rep(i, n) s[x[i]] += y[i];
    
    ll ans = 0;
    for (int i = w; i <= m; ++i) {
        ll now = 0;
        for (int j = i; j <= m; j += i) now += s[j];
        ans = max(ans, now);
    }
    
    cout << ans << '\n';
    
    return 0;
}