//header
#ifdef LOCAL
    #include "cxx-prettyprint-master/prettyprint.hpp"
    #define print(x) cout << x << endl
#else
    #define print(...) 42
#endif
    #pragma GCC optimize("Ofast")
    #include <bits/stdc++.h>
    //types
    using namespace std;
    using ll = long long;
    typedef pair < ll , ll >Pl;
    typedef pair < int, int >Pi;
    typedef vector<ll> vl;
    template< typename T >
    using mat = vector< vector< T > >;
    template <std::uint_fast64_t Modulus> class modint {
        using u64 = std::uint_fast64_t;

        public:
        u64 a;

        constexpr modint(const u64 x = 0) noexcept : a(x % Modulus) {}
        constexpr u64 &value() noexcept { return a; }
        constexpr const u64 &value() const noexcept { return a; }
        constexpr modint operator+(const modint rhs) const noexcept {
            return modint(*this) += rhs;
        }
        constexpr modint operator-(const modint rhs) const noexcept {
            return modint(*this) -= rhs;
        }
        constexpr modint operator*(const modint rhs) const noexcept {
            return modint(*this) *= rhs;
        }
        constexpr modint operator/(const modint rhs) const noexcept {
            return modint(*this) /= rhs;
        }
        constexpr modint &operator+=(const modint rhs) noexcept {
            a += rhs.a;
            if (a >= Modulus) {
            a -= Modulus;
            }
            return *this;
        }
        constexpr modint &operator-=(const modint rhs) noexcept {
            if (a < rhs.a) {
            a += Modulus;
            }
            a -= rhs.a;
            return *this;
        }
        constexpr modint &operator*=(const modint rhs) noexcept {
            a = a * rhs.a % Modulus;
            return *this;
        }
        constexpr modint &operator/=(modint rhs) noexcept {
            u64 exp = Modulus - 2;
            while (exp) {
            if (exp % 2) {
                *this *= rhs;
            }
            rhs *= rhs;
            exp /= 2;
            }
            return *this;
        }
        };
    //abbreviations
    #define all(x) (x).begin(), (x).end()
    #define rall(x) (x).rbegin(), (x).rend()
    #define reverse(x) (x).rbegin(), (x).rend()
    #define rep2(i,a,b) for(int i=(a);i<(b);++i)
    #define rep(i,n) for(int i=0;i<(n);++i)
    #define rev(i,n) for(int i=n-1;i>=0;i--)
    #define SZ(x) ((ll)(x).size())
    #define pb(x) push_back(x)
    #define ff first
    #define ss second
    #define mp make_pair
    //functions
    ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; }
    template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
    template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
    template< typename T >
    T mypow(T x, ll n) {
        T ret = 1;
        while(n > 0) {
            if(n & 1) (ret *= x);
            (x *= x);
            n >>= 1;
        }
        return ret;
    }
    uint64_t my_rand(void) {
        static uint64_t x = 88172645463325252ULL;
        x = x ^ (x << 13); x = x ^ (x >> 7);
        return x = x ^ (x << 17);
    }
    //graph template
    template< typename T >
    struct edge {
        int src, to;
        T cost;

        edge(int to, T cost) : src(-1), to(to), cost(cost) {}

        edge(int src, int to, T cost) : src(src), to(to), cost(cost) {}

        edge &operator=(const int &x) {
        to = x;
        return *this;
    }

    operator int() const { return to; }
    };

    template< typename T >
    using Edges = vector< edge< T > >;
    template< typename T >
    using WeightedGraph = vector< Edges< T > >;
    using UnWeightedGraph = vector< vector< int > >;

//constant
#define INF 1'010'000'000'000'000'017LL
#define mod 1000003LL
typedef modint<mod> mint;
#define eps 0.000001
const double PI = M_PI;
//library
/* 基本要素 */
//main
int main(){
    int N; cin>>N;
    multiset<Pl> R, L;
    rep(_, N){
        ll l, r;
        cin>>l>>r;
        R.insert(mp(r, l)); L.insert(mp(l, r));
    }
    multiset<Pl> R1 = R, L1 = L;
    ll now = 0;
    ll K = 0;
    rep(i, N){
        if(i%2 == 0){
            Pl p = *R.begin();
            ll r = p.first, l = p.second;
            R.erase(R.begin());
            L.erase(L.find(mp(l, r)));
            if(now>=r){
                K+=abs(now-r);
                now = r;
            }
        }else{
            Pl p = *L.rbegin();
            ll r = p.second, l = p.first;
            L.erase(L.find(p));
            R.erase(R.find(mp(r, l)));
            if(now<=l){
                K+=abs(now-l);
                now = l;
            }
        }
    }
    K+=abs(now);
    ll ans = K;
    K = 0;
    now = 0;
    R = R1; L = L1;
    rep(i, N){
        if(i%2 == 1){
            Pl p = *R.begin();
            ll r = p.first, l = p.second;
            R.erase(R.begin());
            L.erase(L.find(mp(l, r)));
            if(now>=r){
                K+=abs(now-r);
                now = r;
            }
        }else{
            Pl p = *L.rbegin();
            ll r = p.second, l = p.first;
            L.erase(L.find(p));
            R.erase(R.find(mp(r, l)));
            if(now<=l){
                K+=abs(now-l);
                now = l;
            }
        }
    }
    K+=abs(now);
    chmax(ans, K);
    cout << ans << endl;
}

Measured memory_bytes: 25216