import sys
def main():
    data=sys.stdin.buffer.read().split()
    N,W=int(data[0]),int(data[1])
    X=list(map(int,data[2:2+N]))
    Y=list(map(int,data[2+N:2+2*N]))
    M=max(X)
    s=[0]*(M+1)
    for x,y in zip(X,Y):s[x]+=y
    ans=0
    for g in range(W,M+1):
        t=0
        for k in range(g,M+1,g):t+=s[k]
        if t>ans:ans=t
    print(ans)
main()