n = input()
a = map(int, raw_input().split())
b = map(int, raw_input().split())
c = map(int, raw_input().split())
ans = 0
for i in range(n):
    ans = ans + b[i]
for i in range(n-1):
    if a[i+1] - a[i] == 1:
        ans += c[a[i]-1]
print ans
