'use strict';

function main(stdin) {
  const input = stdin.split('\n');
  const N = Number(input.shift());
  const params = input.map(p => p.split(' ').map(v => parseInt(v, 10)));

  const A = params[0];
  const B = params[1];
  const C = params[2];
  
  let ans = 0;

  ans += B[A[0] - 1];

  A.reduce((a, b) => {
    ans += B[b - 1];
    if (b - a === 1) ans += C[a - 1];
    return b;
  });
  
  console.log(ans);
}

main(require('fs').readFileSync('/dev/stdin', 'utf8').trim());