import sys
from collections import defaultdict
input = sys.stdin.readline
def solve():
    N, W = map(int, input().split())
    X = list(map(int, input().split()))
    Y = list(map(int, input().split()))
    max_X = max(X)
    total_Y = defaultdict(int)
    for xi,yi in zip(X,Y): total_Y[xi] += yi
    ans = 0
    for d in range(W, max_X+1):
        s = sum(total_Y[v] for v in range(d, max_X+1, d))
        ans = max(ans, s)
    print(ans)
solve()