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

ll W[200000],V[200000],a[200001];
int main() {
    int n,w;
    cin >> n >> w;
    for(int i = 0; i < n; i++){
        cin >> W[i];
    }
    for(int i = 0; i < n; i++){
        cin >> V[i];
    }
    for(int i = 0; i < n; i++){
        a[W[i]] += V[i];
    }
    ll ans = 0;
    for(int i = w; i <= 200000; i++){
        ll now = 0;
        for(int j = i; j <= 200000; j += i){
            now += a[j];
        }
        ans = max(ans, now);
    }
    cout << ans << endl;
}