import sys
input = sys.stdin.readline

def solve():
    n, w = map(int, input().split())
    x = list(map(int, input().split()))
    y = list(map(int, input().split()))

    mx = max(x)
    val = [0] * (mx + 1)

    for i in range(n):
        val[x[i]] += y[i]

    ans = 0

    for g in range(w, mx + 1):
        s = 0
        for v in range(g, mx + 1, g):
            s += val[v]
        if s > ans:
            ans = s

    print(ans)

if __name__ == "__main__":
    solve()