N = int(raw_input())
A = raw_input().split()
B = raw_input().split()
C = raw_input().split()


satis = 0
for i in range(N):
    satis = satis + int(B[int(A[i])-1])
    if i >0:
        if int(A[i]) == int(A[i-1])+1:
            satis = satis + int(C[int(A[i])-2])

print satis

