if (__name__ == '__main__'):
    a = [0]
    b = [0]
    c = [0]

    aa = input().strip().split()
    for i in range(n):
        a.append(int(aa[i]))
    bb = input().strip().split()
    for i in range(n):
        b.append(int(bb[i]))
    cc = input().strip().split()
    for i in range(n-1):
        c.append(int(cc[i]))

    sum = b[a[1]]
    lastmenu = a[1]

    for i in range(2, n+1):
        sum = sum + b[a[i]]
        if (a[i] == lastmenu+1):
            sum = sum + c[lastmenu]
        lastmenu = a[i]

    print(sum)
