import sys

input = sys.stdin.readline

n, w = map(int, input().split())
xs = list(map(int, input().split()))
ys = list(map(int, input().split()))

mx = 200000
cnt = [0] * (mx + 1)

for x, y in zip(xs, ys):
    cnt[x] += y

best = 0

for g in range(w, mx + 1):
    cur = 0
    for j in range(g, mx + 1, g):
        cur += cnt[j]
    if cur > best:
        best = cur

print(best)