_ = input().strip()
a = input().strip().split(" ")
b = input().strip().split(" ")
c = input().strip().split(" ")

m = 0
pre_a = -1
for _a in a:
    
    _a = int(_a)
    _a -= 1
    m += int(b[_a])
    
    if pre_a+1 == _a:
        m += int(c[pre_a])
    pre_a = _a
    
print(m)