N,Q=map(int,input().split())
A=list(map(int,input().split()))
B=list(map(int,input().split()))
T={}
C=set(A)
C=list(C)
C.sort()
for i in range(len(C)):
  T[C[i]]=i
M=len(C)
R=[set() for i in range(M)]
for i in range(N):
  R[T[A[i]]].add(i)
L=[0]
dp=[[10**15]*N for i in range(Q+1)]
dp[0][0]=0
from bisect import bisect_right
for i in range(Q):
  L2=[]
  for j in range(N):
    if A[j]==B[i]:
      L2.append(j)
      pos=bisect_right(L,j)
      if pos>0:
        dp[i+1][j]=min(dp[i][L[pos-1]]+j-L[pos-1],dp[i+1][j])
      if pos<len(L):
        dp[i+1][j]=min(dp[i+1][j],dp[i][L[pos]]+L[pos]-j)
  L=L2[:]
print(min(dp[Q]))