#include <stdio.h>

#define MAXX 200000

long long sumVal[MAXX + 1];

int main(void) {
    int N, W;
    scanf("%d %d", &N, &W);

    int X[200005];
    long long Y[200005];

    for (int i = 0; i < N; i++) {
        scanf("%d", &X[i]);
    }
    for (int i = 0; i < N; i++) {
        scanf("%lld", &Y[i]);
        sumVal[X[i]] += Y[i];
    }

    long long ans = 0;

    for (int d = W; d <= MAXX; d++) {
        long long cur = 0;
        for (int multiple = d; multiple <= MAXX; multiple += d) {
            cur += sumVal[multiple];
        }
        if (cur > ans) ans = cur;
    }

    printf("%lld\n", ans);
    return 0;
}