#include "bits/stdc++.h"

using namespace std;
#ifdef _DEBUG
#define _GLIBCXX_DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define ll long long
#define ll1 1ll
#define ONE 1ll
#define DBG 1
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define rrep(i, a, b) for (int i = (b)-1; i >= (a); i--)
#define loop(n) rep(loop, (0), (n))
#define all(c) begin(c), end(c)
const int INF =
sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9) + 7;
const double PI = acos(-1);
const double EPS = 1e-9;
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
using pii = pair<int, int>;
// template<class T> ostream &operator<<(ostream &os,T &t){dump(t);return os;}
template <typename T, typename S>
istream &operator>>(istream &is, pair<T, S> &p) {
	is >> p.first >> p.second;
	return is;
}
template <typename T, typename S>
ostream &operator<<(ostream &os, pair<T, S> &p) {
	os << p.first << " " << p.second;
	return os;
}

template <typename T> void printvv(const vector<vector<T>> &v) {
	cerr << endl;
	rep(i, 0, v.size()) rep(j, 0, v[i].size()) {
		if (typeid(v[i][j]).name() == typeid(INF).name() and v[i][j] == INF) {
			cerr << "INF";
		}
		else
			cerr << v[i][j];
		cerr << (j == v[i].size() - 1 ? '\n' : ' ');
	}
	cerr << endl;
}
/*
typedef __int128_t Int;
std::ostream &operator<<(std::ostream &dest, __int128_t value) {
std::ostream::sentry s(dest);
  if (s) {
	__uint128_t tmp = value < 0 ? -value : value;
	char buffer[128];
	char *d = std::end(buffer);
	do {
	  --d;
	  *d = "0123456789"[tmp % 10];
	  tmp /= 10;
	} while (tmp != 0);
	if (value < 0) {
	  --d;
	  *d = '-';
	}
	int len = std::end(buffer) - d;
	if (dest.rdbuf()->sputn(d, len) != len) {
	  dest.setstate(std::ios_base::badbit);
	}
  }
  return dest;
}

__int128 parse(string &s) {
  __int128 ret = 0;
  for (int i = 0; i < s.length(); i++)
	if ('0' <= s[i] && s[i] <= '9')
	  ret = 10 * ret + s[i] - '0';
  return ret;
}
*/

#ifndef _DEBUG
#define printvv(...)
#endif
void YES(bool f) { cout << (f ? "YES" : "NO") << endl; }
void Yes(bool f) { cout << (f ? "Yes" : "No") << endl; }
template <class T> bool chmax(T &a, const T &b) {
	if (a < b) {
		a = b;
		return true;
	}
	return false;
}
template <class T> bool chmin(T &a, const T &b) {
	if (a > b) {
		a = b;
		return true;
	}
	return false;
}

signed main(signed argc, char *argv[]) {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed << setprecision(12);

	int N; cin >> N;
	vector<pii>L(N), R(N);
	rep(i, 0, N) {
		cin >> L[i].first >> R[i].first;
		L[i].second = R[i].second = i;
	}
	sort(all(L)); sort(all(R));
	dump(L);
	dump(R);
	vector<int>used(N);
	int ans1 = 0;
	int cur = 0;
	int l = N - 1, r = 0;
	rep(i, 0, N) {
		dump(cur, l, r, ans1, used);
		if (i & 1) {
			while (used[R[r].second])r++;
			ans1 += max(cur - R[r].first, 0ll);
			if (max(cur - R[r].first, 0ll) == 0)break;
			used[R[r].second] = 1;
			cur = R[r].first;
		}
		else {
			while (used[L[l].second])l--;
			ans1 += max(L[l].first - cur, 0ll);
			dump(ans1);
			if (max(L[l].first - cur, 0ll)==0)break;
			used[L[l].second] = 1;
			cur = L[l].first;
		}
	}
	ans1 += abs(cur);
	int ans2 = 0;
	cur = 0;
	l = N - 1, r = 0;
	used.assign(N, 0);
	rep(i, 0, N) {
		if (i % 2 == 0) {
			while (used[R[r].second])r++;
			ans2 += max(cur - R[r].first, 0ll);
			if (max(cur - R[r].first, 0ll) == 0)break;
			used[R[r].second] = 1;
			cur = R[r].first;
		}
		else {
			while (used[L[l].second])l--;
			ans2 += max(L[l].first - cur, 0ll);
			if (max(L[l].first - cur, 0ll)==0)break;
			used[L[l].second] = 1;
			cur = L[l].first;
		}
	}
	ans2 += abs(cur);
	cout << max(ans1, ans2) << endl;
	return 0;
}


Measured memory_bytes: 4224