#include <bits/stdc++.h>

using i32 = int32_t;
using ui32 = uint32_t;
using i64 = int64_t;
using ui64 = uint64_t;

using namespace std;


i32 main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  int n;
  cin >> n;
  vector<pair<int,int>> arr(n);
  int mnx = 1e6;
  int mny = 1e6;
  int mxx = -1e6;
  int mxy = -1e6;
  for (int i = 0; i < n; i++) {
    int x, y;
    cin >> x >> y;
    arr[i] = {x, y};

    mnx = min(mnx, x - 1);
    mny = min(mny, y - 1);

    mxx = max(mxx, x + 1);
    mxy = max(mxy, y + 1);
  }

  pair<int,int> A = {mnx, mny},
                B = {mnx, mxy},
                C = {mxx, mxy},
                D = {mxx, mxy};
  double answer = (mxx - mnx) * 2 + (mxy - mny) * 2;

  {
    int k = 1e7;
    for (int i = 0; i < n; i++) {
      int x = arr[i].first;
      int y = arr[i].second;
      x -= A.first;
      y -= A.second;
      k = min(k, x + y - 1);
    }
    answer -= k * 2;
    answer += k * sqrt(2);
  }


  {
    for (int i = 0; i < n; i++) {
      arr[i].second = mxy - arr[i].second;
    }
    B.second = mxy - B.second;

    int k = 1e7;
    for (int i = 0; i < n; i++) {
      int x = arr[i].first;
      int y = arr[i].second;
      x -= B.first;
      y -= B.second;
      k = min(k, x + y - 1);
    }
    answer -= k * 2;
    answer += k * sqrt(2);

    for (int i = 0; i < n; i++) {
      arr[i].second = mxy - arr[i].second;
    }
  }

  {
    for (int i = 0; i < n; i++) {
      arr[i].second = mxy - arr[i].second;
      arr[i].first = mxx - arr[i].first;
    }

    C.first = 0;
    C.second = 0;

    int k = 1e7;
    for (int i = 0; i < n; i++) {
      int x = arr[i].first;
      int y = arr[i].second;
      x -= B.first;
      y -= B.second;
      k = min(k, x + y - 1);
    }
    answer -= k * 2;
    answer += k * sqrt(2);

    for (int i = 0; i < n; i++) {
      arr[i].second = mxy - arr[i].second;
      arr[i].first = mxx - arr[i].first;
    }
  }


  {
    for (int i = 0; i < n; i++) {
      arr[i].first = mxx - arr[i].first;
    }
    D.first = 0;

    int k = 1e7;
    for (int i = 0; i < n; i++) {
      int x = arr[i].first;
      int y = arr[i].second;
      x -= B.first;
      y -= B.second;
      k = min(k, x + y - 1);
    }
    answer -= k * 2;
    answer += k * sqrt(2);

    for (int i = 0; i < n; i++) {
      arr[i].first = mxx - arr[i].first;
    }
  }


  cout << fixed << setprecision(15) << answer << endl;
}