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])
	}
	// 解説を読んだ
	// 解説のやりかた試す
	sum := make([]int, 2e5+1)
	for i, x := range xs {
		sum[x] += ys[i]
	}
	ans := 0
	for g := w; g <= 2e5; g++ {
		tmp := 0
		for e := g; e <= 2e5; e += g {
			tmp += sum[e]
		}
		ans = max(ans, tmp)
	}
	Println(ans)
}