import sys

def solve() -> None:
    data = list(map(int, sys.stdin.buffer.read().split()))
    if not data:
        return

    it = iter(data)
    N = next(it)
    W = next(it)

    X = [next(it) for _ in range(N)]
    Y = [next(it) for _ in range(N)]

    M = max(X)
    sum_by_weight = [0] * (M + 1)

    for x, y in zip(X, Y):
        sum_by_weight[x] += y

    ans = 0
    if W <= M:
        m_plus_1 = M + 1
        arr = sum_by_weight
        for d in range(W, m_plus_1):
            s = 0
            for multiple in range(d, m_plus_1, d):
                s += arr[multiple]
            if s > ans:
                ans = s

    print(ans)

if __name__ == "__main__":
    solve()