inf = 1 << 61
N,Q = map(int,input().split())
A = list(map(int,input().split()))
B = list(map(int,input().split()))
dp = [[inf for j in range(N)] for i in range(Q+1)]
dp[0][0] = 0
for q in range(Q):
  b = B[q]
  X = []
  for i in range(N):
    if A[i] == b:
      X.append(i)
  L = [dp[q][i] - i for i in range(N)]
  R = [dp[q][i] + i for i in range(N)]
  for i in range(N-1):
    L[i+1] = min(L[i+1],L[i])
  for i in range(N-1,0,-1):
    R[i-1] = min(R[i-1],R[i])
  for i in X:
    dp[q+1][i] = min(L[i] + i,R[i] - i)
print(min(dp[Q]))