from collections import defaultdict
import bisect
n,q=map(int,input().split())
A=list(map(int,input().split()))
B=list(map(int,input().split()))
D=defaultdict(list)
for i,j in enumerate(A):
    D[j].append(i)
D1=defaultdict(lambda:10**10)
D1[0]=0
for i in B:
    D2=defaultdict(lambda:10**10)
    for ii,jj in D1.items():
        c=bisect.bisect_left(D[i],ii)
        for k in range(-1,1):
            c1=c+k
            if 0<=c1<len(D[i]):
                D2[D[i][c1]]=min(D2[D[i][c1]],jj+abs(ii-D[i][c1]))
    D1=D2
print(min(i for i in D1.values()))