var a,b,c,sum;
function Main(input){
    i=input.split("\n")
    a=i[1].split(" ").map(Number);
    b=i[2].split(" ").map(Number);
    c=i[3].split(" ").map(Number);
    solve(0,0)
    console.log(ans)
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));
function solve(nowi,sum){
    if(nowi>0&&a[nowi-1]===a[nowi]-1){sum+=c[a[nowi]-2];}
    sum+=b[a[nowi]-1]
    if(nowi>=a.length-1){
        ans=sum}
    else solve(nowi+1,sum);
}