from bisect import bisect_left
N,W = map(int, input().split())
X = list(map(int, input().split()))
Y = list(map(int, input().split()))
C = {}
for i in range(N):
    x = X[i]
    y = Y[i]
    C[x] = C.get(x,0)+y
C = sorted(C.items())
xmin = C[0][0]
xmax = C[-1][0]
ans = 0
for w in range(W,xmax+1):
    cnt = 0
    for k in range(1,xmax//w+1):
        x = w*k
        i = bisect_left(C, (x,0))
        if C[i][0]==x:
            cnt += C[i][1]
    ans = max(ans, cnt)
print(ans)