/* -*- coding: utf-8 -*-
 *
 * 3502.cc:  No.3502 GCD Knapsack - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 200000;
const int MAX_X = 200000;

/* typedef */

using ll = long long;

/* global variables */

int xs[MAX_N], ys[MAX_N];
ll yss[MAX_X + 1];

/* subroutines */

/* main */

int main() {
  int n, w;
  scanf("%d%d", &n, &w);
  for (int i = 0; i < n; i++) scanf("%d", xs + i);
  for (int i = 0; i < n; i++) scanf("%d", ys + i);

  for (int i = 0; i < n; i++) {
    for (int p = 1; p * p <= xs[i]; p++)
      if (xs[i] % p == 0) {
	if (p >= w) yss[p] += ys[i];
	int q = xs[i] / p;
	if (q != p && q >= w) yss[q] += ys[i];
      }
  }

  ll maxysum = *max_element(yss + w, yss + MAX_X + 1);
  printf("%lld\n", maxysum);
  
  return 0;
}