#include <iostream>
#include <algorithm>

using namespace std;
#define MAX 1000000
int main() {
    int n;
    cin >> n;

    pair<int, int> coords[n];
    for (int i = 0; i < n; i++) {
        cin >> coords[i].first >> coords[i].second;
    }

    sort(coords, coords+n);

//    for(int i = 0; i < n; i++) {
//        cout << coords[i].first << " " << coords[i].second << endl;
//    }

    //long long min = MAX, max = -MAX;

   // int prev_x = coords[0].first, prev_y = coords[0].second;

    int sum = 0;

    int prev_min, prev_max, prev_y;

    for(int i = 0; i < n;) {

//        sum += abs(coords[i].first - prev_x);
  //      sum += abs(coords[i].second - prev_y);
      //  prev_x = coords[i].first;
    //    prev_y = coords[i].second;


        int ind = i;
        int curr_min_x = coords[ind].second;
        int curr_max_x = coords[ind].second;

        int curr_y = coords[ind].first;

        if(i < n-1) {
            ind++;

            while (1) {
                if (coords[ind].first == coords[ind - 1].first) {
                    curr_max_x = coords[ind].second;
                } else {
                    break;
                }
                ind++;
            }
        } else  {
            ind++;
        }

        sum += curr_max_x - curr_min_x;
       // cout << "sum" << " " << sum << endl;

        if(i >= 1) {
            sum += abs(prev_y - curr_y);
            sum += min(min(abs(prev_max - curr_min_x), abs(prev_min - curr_max_x)), min(abs(prev_max - curr_max_x), abs(prev_min - curr_min_x)));
            //cout << sum << endl;
        }

        prev_min = curr_min_x;
        prev_max = curr_max_x;
        prev_y = curr_y;
        i = ind;

    }

    cout << sum << endl;

    return 0;
}