N=int(input())
A=list(map(int,input().split()))
pos=[0 for i in range(N)]
for i in range(N):
    pos[A[i]-1]=i
B=list(map(int,input().split()))
prev=-1
chunk=0
ans=0
for i in B:
    if prev>pos[i-1]:
        chunk+=1
    prev=pos[i-1]
while chunk>0:
	ans+=1
	chunk//=2
print(ans)