import sys
input = sys.stdin.readline
from math import gcd
from bisect import bisect

# エラトステネスの篩を用いた素因数分解・約数列挙
MAX=10**5+10 # 使いたい最大値を指定

# Sieve[i]で、iの最も小さい1でない約数を返す。
Sieve=[i for i in range(MAX)]

for i in range(2,MAX):
    if Sieve[i]!=i:
        continue
    
    for j in range(i,MAX,i):
        if Sieve[j]==j:
            Sieve[j]=i


# 素因数分解
def fact(x):
    D=dict()
    while x!=1:
        k=Sieve[x]
        if k in D:
            D[k]+=1
        else:
            D[k]=1
        x//=k
    return D

# 約数列挙
def faclist(x):
    LIST=[1]
    while x!=1:
        k=Sieve[x]
        count=0
        while x%k==0:
            count+=1
            x//=k

        LIST2=[]
        for l in LIST:
            for i in range(1,count+1):
                LIST2.append(l*k**i)
        LIST+=LIST2

    return LIST

N,K=list(map(int,input().split()))
A=list(map(int,input().split()))
B=list(map(int,input().split()))

LL=[]
for i in range(N):
    a=A[i]
    b=B[i]
    
    F=faclist(a)
    LIST=[]

    for f in F:
        k=(b+f-1)//f*f
        need=k-b

        LIST.append((f,need))

    LIST2=[]
    for x,y in LIST:
        while LIST2 and LIST2[-1][1]>=y:
            LIST2.pop()
        LIST2.append((x,y))

    LL.append(LIST2)

OK=0
NG=1<<60

while NG>OK+1:
    mid=(OK+NG)//2

    score=0

    for i in range(N):
        k=bisect(LL[i],(mid,-1))

        if k==len(LL[i]):
            score=1<<63
            break
        else:
            score+=LL[i][k][1]

    if score<=K:
        OK=mid
    else:
        NG=mid

print(OK)