n = int(raw_input())

x = lambda: map(int, raw_input().strip().split())

A = x()
B = x()
C = x()

points = 0
for i in xrange(n):
  points += B[A[i]-1]
  if i > 0 and A[i] == A[i-1] + 1:
    points += C[A[i]-2]

print points
