n,w = map(int, input().split())
x = list(map(int, input().split()))
y = list(map(int, input().split()))
a = [0] * 500001
for i in range(n):
    a[x[i]] += y[i]

ans = 0
for i in range(w,500001):
    now = 0
    for j in range(i,500001,i):
        now += a[j]
    ans = max(ans, now)
print(ans)