#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;

template <typename T1, typename T2>
string print_iterable(T1 begin_iter, T2 end_iter, int counter) {
    bool done_something = false;
    stringstream res;
    res << "[";
    for (; begin_iter != end_iter and counter; ++begin_iter) {
        done_something = true;
        counter--;
        res << *begin_iter << ", ";
    }
    string str = res.str();
    if (done_something) {
        str.pop_back();
        str.pop_back();
    }
    str += "]";
    return str;
}

vector<int> SortIndex(int size, std::function<bool(int, int)> compare) {
    vector<int> ord(size);
    for (int i = 0; i < size; i++) ord[i] = i;
    sort(ord.begin(), ord.end(), compare);
    return ord;
}

template <typename T>
bool MinPlace(T& a, const T& b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}

template <typename T>
bool MaxPlace(T& a, const T& b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template <typename Container>
int SZ(const Container& S) { return S.size(); }

template <typename S, typename T>
ostream& operator <<(ostream& out, const pair<S, T>& p) {
    out << "{" << p.first << ", " << p.second << "}";
    return out;
}

template <typename T>
ostream& operator <<(ostream& out, const vector<T>& v) {
    out << "[";
    for (int i = 0; i < (int)v.size(); i++) {
        out << v[i];
        if (i != (int)v.size()-1) out << ", ";
    }
    out << "]";
    return out;
}

#if DEBUG && !ONLINE_JUDGE
    ifstream input_from_file("input.txt");
    #define cin input_from_file

    #define dbg_var(x) clog << #x  << ": " << x << endl;
    #define dbg_array(x, len) clog << #x << ": " << print_iterable(x, x+len, -1) << endl;
#else
    #define dbg_var(x)
    #define dbg_array(x, len)
#endif

///////////////////////////////////////////////////////////////////////////
//////////////////// DO NOT TOUCH BEFORE THIS LINE ////////////////////////
///////////////////////////////////////////////////////////////////////////

const int MAXN = 100100;
int N;
LL L[MAXN], R[MAXN];

LL solve() {
    typedef pair<int,int> pii;
    priority_queue<pii, vector<pii>, std::greater<pii>> RP;
    priority_queue<pii> LP;
    vector<bool> used(N, false);
    for (int i = 0; i < N; i++) {
        LP.push({L[i], i});
        RP.push({R[i], i});
    }
    int it = 0;
    LL res = 0;
    for (int i = 0; ; i++) {
        // cout << i << endl;
        if (i%2 == 0) {
            while (!LP.empty() and used[LP.top().second]) LP.pop();
            if (LP.empty() or LP.top().first <= it) {
                res += abs(it - 0);
                break;
            }
            int new_it = LP.top().first;
            res += abs(it-new_it);
            it = new_it;
            used[LP.top().second] = true;
            LP.pop();
        } else {
            while (!RP.empty() and used[RP.top().second]) RP.pop();
            if (RP.empty() or RP.top().first >= it) {
                res += abs(it - 0);
                break;
            }
            int new_it = RP.top().first;
            res += abs(it-new_it);
            it = new_it;
            used[RP.top().second] = true;
            RP.pop();
        }
    }
    return res;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0); // Remove in problems with online queries!
    cin >> N;
    for (int i = 0; i < N; i++) {
        cin >> L[i] >> R[i];
    }
    LL res = solve();
    for (int i = 0; i < N; i++) {
        swap(L[i], R[i]);
        L[i] = -L[i], R[i] = -R[i];
    }
    res = max(res, solve());
    cout << res << "\n";
}


Measured memory_bytes: 4812