import sys
input = sys.stdin.readline

N,W=list(map(int,input().split()))
X=list(map(int,input().split()))
Y=list(map(int,input().split()))

OK=[0]*200001
LANS=0

for i in range(W,200001):
    if OK[i]==1:
        continue

    w=i
    for j in range(w,200001,w):
        OK[j]=1

    ANS=0

    for i in range(N):
        if X[i]%w==0:
            ANS+=Y[i]

    LANS=max(LANS,ANS)

print(LANS)