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

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

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

      vector<int> X(N);
      for (int i = 0; i < N; i++) cin >> X[i];

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

      const int MAXX = 200000;
      vector<long long> S(MAXX + 1, 0);

      for (int i = 0; i < N; i++) {
          S[X[i]] += Y[i];
      }

      long long ans = 0;

      for (int d = W; d <= MAXX; d++) {
          long long sum = 0;
          for (int m = d; m <= MAXX; m += d) {
              sum += S[m];
          }
          ans = max(ans, sum);
      }

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