import sys

readline = sys.stdin.readline
input_value = readline().split()
N = input_value[0]
K = input_value[1]

Weight = map(int, readline().split())
Value = map(int, readline().split())

M = max(Weight)

val_sum = [0] * (M + 1)
for i in range(N):
    w = Weight[i]
    v = Value[i]
    if v > 0:
        val_sum[w] += v

ans = 0

for g in range(K + 1, M + 1):
    current_value = 0
    for w in range(g, M + 1, g):
        current_value += val_sum[w]

    if current_value > ans:
        ans = current_value

print(ans)