'use strict';
const main = val => {
  const n = parseInt(val[0], 10);
  const a = val[1].split(' ').map(p => parseInt(p, 10));
  const b = val[2].split(' ').map(p => parseInt(p, 10));
  const c = val[3].split(' ').map(p => parseInt(p, 10));
  var ans = 0;
  b.map(val => ans += val);
  for (let i = 0; i < a.length - 1; i++) {
    ans += a[i+1]-a[i] == 1 ? c[a[i]-1] : 0;
  }
  console.log(ans);
}
main(require("fs").readFileSync("/dev/stdin", "utf8").split('\n'));