#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < int(n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define reps(i, n) for (int i = 1; i <= int(n); i++)
#define rreps(i, n) for (int i = int(n); i >= 1; i--)
#define repc(i, n) for (int i = 0; i <= int(n); i++)
#define rrepc(i, n) for (int i = int(n); i >= 0; i--)
#define repi(i, a, b) for (int i = int(a); i < int(b); i++)
#define repic(i, a, b) for (int i = int(a); i <= int(b); i++)
#define all(a) (a).begin(), (a).end()
#define bit32(x) (1 << (x))
#define bit64(x) (1ll << (x))
#define sz(v) ((int) v.size())

using namespace std;

using i64 = long long;
using f80 = long double;
using vi32 = vector<int>;
using vi64 = vector<i64>;
using vf80 = vector<f80>;
using vstr = vector<string>;

void yes() { cout << "Yes" << endl; exit(0); }
void no() { cout << "No" << endl; exit(0); }
template <typename T> class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template <typename T> class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template <typename T> void amax(T &x, T y) { x = max(x, y); }
template <typename T> void amin(T &x, T y) { x = min(x, y); }
template <typename T> T exp(T x, i64 n, T e = 1) { T r = e; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
template <typename T> istream& operator>>(istream &is, vector<T> &v) { for (auto &x : v) is >> x; return is; }
template <typename T> ostream& operator<<(ostream &os, vector<T> &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; }
void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; }

const int INF = 1001001001;
const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};

void solve() {
  int n;
  cin >> n;
  vi32 L(n), R(n);
  rep(i, n) {
    cin >> L[i] >> R[i];
  }
  i64 ans = 0;
  using P = pair<int, int>;
  {
    map<P, int, less<P>> rmins;
    map<P, int, greater<P>> lmaxs;
    auto remove = [&](int l, int r) {
      rmins[P(r, l)]--;
      if (rmins[P(r, l)] == 0) rmins.erase(P(r, l));
      lmaxs[P(l, r)]--;
      if (lmaxs[P(l, r)] == 0) lmaxs.erase(P(l, r));
    };
    i64 acc = 0;
    int now = 0;
    rep(i, n) {
      rmins[P(R[i], L[i])]++;
      lmaxs[P(L[i], R[i])]++;
    }
    rep(i, n) {
      int l, r;
      if (i % 2 == 0) {
        r = rmins.begin()->first.first;
        l = rmins.begin()->first.second;
      } else {
        l = lmaxs.begin()->first.first;
        r = lmaxs.begin()->first.second;
      }
      if (l > now) {
        acc += l - now;
        now = l;
      } else if (r < now) {
        acc += now - r;
        now = r;
      }
      remove(l, r);
    }
    acc += abs(now);
    amax(ans, acc);
    acc = 0;
    now = 0;
    rep(i, n) {
      rmins[P(R[i], L[i])]++;
      lmaxs[P(L[i], R[i])]++;
    }
    rep(i, n) {
      int l, r;
      if (i % 2 == 1) {
        r = rmins.begin()->first.first;
        l = rmins.begin()->first.second;
      } else {
        l = lmaxs.begin()->first.first;
        r = lmaxs.begin()->first.second;
      }
      if (l > now) {
        acc += l - now;
        now = l;
      } else if (r < now) {
        acc += now - r;
        now = r;
      }
      remove(l, r);
    }
    acc += abs(now);
    amax(ans, acc);
  }
  cout << ans << endl;
}


Measured memory_bytes: 16400