import sys

def solve():
    input = sys.stdin.readline
    N, W = map(int, input().split())
    X = list(map(int, input().split()))
    Y = list(map(int, input().split()))

    maxX = max(X) if X else 0
    val = [0] * (maxX + 1)
    for x, y in zip(X, Y):
        val[x] += y

    S = [0] * (maxX + 1)
    for g in range(1, maxX + 1):
        total = 0
        for m in range(g, maxX + 1, g):
            total += val[m]
        S[g] = total

    ans = 0
    for g in range(W, maxX + 1):
        if S[g] > ans:
            ans = S[g]
    print(ans)

if __name__ == "__main__":
    solve()