import io
import sys
from collections import defaultdict, deque, Counter
from itertools import permutations, combinations, accumulate
from heapq import heappush, heappop
from bisect import bisect_right, bisect_left
from math import gcd
import math

_INPUT = """\
6
5 4
3 7 1 9 2
1 2 3 7
3 5
7 1 10
7 7 7 7 7
3 2
1 1 2
2 1
"""

def input():
  return sys.stdin.readline()[:-1]

def solve(test):
  N,Q=map(int,input().split())
  A=list(map(int,input().split()))
  B=list(map(int,input().split()))
  D=[0]*N
  d=defaultdict(list)
  for i in range(N):
    d[A[i]].append(i)
  tmp=[(0,0)]
  for i in range(Q):
    tmp2=[]
    now=0
    for g in d[B[i]]:
      while now<len(tmp) and tmp[now][0]<g:
        now+=1
      if now==0:
        tmp2.append((g,tmp[0][1]+tmp[0][0]-g))
      elif now==len(tmp):
        tmp2.append((g,tmp[-1][1]+g-tmp[-1][0]))
      else:
        tmp2.append((g,min(tmp[now][1]+tmp[now][0]-g,tmp[now-1][1]+g-tmp[now-1][0])))
    tmp=tmp2
  print(min([x[1] for x in tmp]))

def random_input():
  from random import randint,shuffle
  N=randint(1,10)
  M=randint(1,N)
  A=list(range(1,M+1))+[randint(1,M) for _ in range(N-M)]
  shuffle(A)
  return (" ".join(map(str, [N,M]))+"\n"+" ".join(map(str, A))+"\n")*3

def simple_solve():
  return []

def main(test):
  if test==0:
    solve(0)
  elif test==1:
    sys.stdin = io.StringIO(_INPUT)
    case_no=int(input())
    for _ in range(case_no):
      solve(0)
  else:
    for i in range(1000):
      sys.stdin = io.StringIO(random_input())
      x=solve(1)
      y=simple_solve()
      if x!=y:
        print(i,x,y)
        print(*[line for line in sys.stdin],sep='')
        break

#0:提出用、1:与えられたテスト用、2:ストレステスト用
main(0)