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

def GCD(a, b):
    while b != 0:
        tmp = b
        b = a % b
        a = tmp
    return a

rng = max(x) - w
if rng < 0:
    print(0)
    exit(0)

dp = [[0 for _ in range(rng+1)] for _ in range(n+1)]

offset = 0
for i in range(n):
    if x[i] < w:
        offset += 1
        continue
    idx = i - offset
    dp[idx+1][x[i]-w] = max(y[i], dp[idx+1][x[i]-w])
    for j in reversed(range(rng)):
        if dp[idx][j] <= 0:
            continue
        dp[idx+1][j] = max(dp[idx][j], dp[idx+1][j])
        gcd = GCD(w+j, x[i])
        if gcd >= w:
            dp[idx+1][gcd-w] = max(dp[idx+1][gcd-w], dp[idx][j]+y[i])

print(max(0,max(dp[n-offset])))