#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef unsigned int uint;
typedef unsigned char uchar;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;

#define REP(i,x) for(int i=0;i<(int)(x);i++)
#define REPS(i,x) for(int i=1;i<=(int)(x);i++)
#define RREP(i,x) for(int i=((int)(x)-1);i>=0;i--)
#define RREPS(i,x) for(int i=((int)(x));i>0;i--)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();i++)
#define RFOR(i,c) for(__typeof((c).rbegin())i=(c).rbegin();i!=(c).rend();i++)
#define ALL(container) (container).begin(), (container).end()
#define RALL(container) (container).rbegin(), (container).rend()
#define SZ(container) ((int)container.size())
#define mp(a,b) make_pair(a, b)
#define pb push_back
#define eb emplace_back
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );

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 (a>b) { a=b; return 1; } return 0; }
template<class T> ostream& operator<<(ostream &os, const vector<T> &t) {
    os<<"["; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"]"; return os;
}
template<class T> ostream& operator<<(ostream &os, const set<T> &t) {
    os<<"{"; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"}"; return os;
}
template<class S, class T> ostream& operator<<(ostream &os, const pair<S,T> &t) { return os<<"("<<t.first<<","<<t.second<<")";}
template<class S, class T> pair<S,T> operator+(const pair<S,T> &s, const pair<S,T> &t){ return pair<S,T>(s.first+t.first, s.second+t.second);}
template<class S, class T> pair<S,T> operator-(const pair<S,T> &s, const pair<S,T> &t){ return pair<S,T>(s.first-t.first, s.second-t.second);}

const int INF = 1<<28;
const double EPS = 1e-8;
const int MOD = 1000000007;

int T, n, m;

ll solve(vector<tuple<int, int>> v) {
    vi li(n), ri(n);
    REP(i, n) {
        li[i] = ri[i] = i;
    }
    sort(ALL(li), [&](int i, int j){
        return get<0>(v[i]) < get<0>(v[j]);
    });
    sort(RALL(ri), [&](int i, int j){
        return get<1>(v[i]) < get<1>(v[j]);
    });
    ll cur = 0, sum = 0;
    set<int> used;
    while(1) {
        while(!li.empty() && used.count(li.back())) {
            li.pop_back();
        }
        if (li.empty()) {
            break;
        }
        {
            int i = li.back();
            int l, r; tie(l, r) = v[i];
            if (l <= cur) break;
            used.insert(i);
            sum += l - cur;
            cur = l;
        }
        while(!ri.empty() && used.count(ri.back())) {
            ri.pop_back();
        }
        if (ri.empty()) {
            break;
        }
        {
            int i = ri.back();
            int l, r; tie(l, r) = v[i];
            if (cur <= r) break;
            used.insert(i);
            sum += cur - r;
            cur = r;
        }
    }
    return sum + abs(cur);
}

int main(int argc, char *argv[]){
    ios::sync_with_stdio(false);
    cin >> n;
    vector<tuple<int, int>> v1, v2;
    REP(i, n) {
        int l, r;
        cin >> l >> r;
        v1.emplace_back(l, r);
        v2.emplace_back(-r, -l);
    }
    cout << max(solve(v1), solve(v2)) << endl;
    return 0;
}


Measured memory_bytes: 8868