#include "testlib.h"

using namespace std;

double sqr(double  x) { return x * x; }

int main(int argc, char* argv[]) {
    registerTestlibCmd(argc, argv);

    int n = inf.readInt();
    vector<pair<int, int> > pts(n);
    for (int i = 0; i < n; i++) {
      pts[i].first = inf.readInt();
      pts[i].second = inf.readInt();
    }

    vector<int> seq(n);
    vector<bool> was(n);
    for (int i = 0; i < n; i++) {
      seq[i] = ouf.readInt(1, n) - 1;
      if (was[seq[i]])
        quitf(_wa, "Vertex %d occurs twice", i + 1);
      was[seq[i]] = true;
    }

    double len = 0;
    for (int i = 1; i < n; i++) {
      int a = seq[i - 1];
      int b = seq[i];
      len += sqrt(sqr(pts[a].first - pts[b].first) + sqr(pts[a].second - pts[b].second));
    }
  quitf(_ok, "length = %.4lf\n%.4lf", len, len);
}