package main

import . "fmt"
import . "os"
import bf "bufio"

func main() {
	rd := bf.NewReader(Stdin)
	var n, w int
	Fscan(rd,&n,&w)
	xs := make([]int, n)
	for i := range xs {
		Fscan(rd,&xs[i])
	}
	ys := make([]int, n)
	for i := range ys {
		Fscan(rd,&ys[i])
	}
	sum := make([]int, 2e5+1)
	for i, x := range xs {
		y := ys[i]
		for p := 1; p*p <= x; p++ {
			if x % p != 0 {
				continue
			}
			q := x / p
			if p >= w {
				sum[p] += y
			}
			if p != q && q >= w {
				sum[q] += y
			}
		}
	}
	ans := 0
	for _, s := range sum[w:] {
		ans = max(ans, s)
	}
	Println(ans)
}