#include <fstream>

using namespace std;
/// inundatii

const int nmax = 5 * 1e4;
struct coord {
  int x, y, z;

}v[nmax + 1];
int main(){

  ifstream fin ("inundatii.in");
  ofstream fout ("inundatii.out");

  int n;

  fin >> n;
  int a, b, c;
  fin >> a >> b >> c;

  int x1,y1,z1;
  int x2, y2, z2;
  int sol = 0;

  for (int i = 2; i <= n; i++){
    fin >> v[i].x >> v[i].y >> v[i].z;
    x1 = (a + v[i].x) / 2;
    y1 = (b + v[i].y) / 2;
    z1 = (c + v[i].z) / 2;

    x2 = x1 + 1;
    y2 = y1 + 1;
    z2 = z1 + 1;

    sol += abs(a - x1) + abs (b - y1) + abs (c - z1) + abs (v[i].x - x2) + abs (v[i].y - y2) + abs (v[i].z - z2);
    a = x2;
    b = y2;
    c = z2;
  }
  fout << sol;
  return 0;
}