n,h=map(int,input().split())
a=[*map(int,input().split()),1<<30]
b=[*map(int,input().split()),1<<30]
m=c=s=r=d=p=0
for i in range(n):
    while s<=h:
        m=max(r,m)
        c+=1
        r+=a[p]
        d+=b[p]
        s+=c*b[p]
        p+=1
    c-=1
    r-=a[i]
    s-=d
    d-=b[i]
print(m)