inf = 10 ** 15

N, Q = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))
dp_left = [0] * N
dp_right = [inf] * N
dp_right[0] = 0
for i in B:
	ndp = [inf] * N
	for j in range(N):
		if A[j] == i:
			ndp[j] = min(dp_left[j] + j, dp_right[j] - j)
	ndp_left = [inf] * N
	ndp_left[0] = ndp[0]
	ndp_right = [inf] * N
	for j in range(1, N):
		ndp_left[j] = min(ndp_left[j - 1], ndp[j] - j)
	ndp_right[N - 1] = ndp[N - 1] + (N - 1)
	for j in range(N - 1, 0, -1):
		ndp_right[j - 1] = min(ndp_right[j], ndp[j - 1] + (j - 1))
	dp_left = ndp_left
	dp_right = ndp_right
print(min(min(dp_left[i] + i for i in range(N)), min(dp_right[i] - i for i in range(N))))