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