function Main(input){
  var N = input.split("\n")[0];
  var A = input.split("\n")[1].split(" ");
  var B = input.split("\n")[2].split(" ");
  var C = input.split("\n")[3].split(" ");
  N = parseInt(N,10);

  for(i=0;i<=(N-1);i++){
    A[i] = parseInt(A[i],10);
    B[i] = parseInt(B[i],10);
  }
  for(i=0;i<=(N-2);i++){
    C[i] = parseInt(C[i],10);
  }

  var sati = 0;
  var jud;
  for(i=0;i<=(N-1);i++){
    jud = A[i] + 1 === A[i+1];
    if(jud===false){
      sati += B[(A[i]-1)];
    }else{
      if(i===(N-1)){
        sati += B[(A[i]-1)];
      }else{
      sati += (B[(A[i]-1)] + C[(A[i]-1)]);
      }
    }
  }
  console.log(sati);
}  

Main(require("fs").readFileSync("/dev/stdin", "utf8"));