#include <bits/stdc++.h>
                                            #include<iostream>
                                            #include<cstdio>
                                            #include<vector>
                                            #include<queue>
                                            #include<map>
                                            #include<cstring>
                                            #include<string>
                                            #include <math.h>
                                            #include<algorithm>
                                        //    #include <boost/multiprecision/cpp_int.hpp>
                                            #include<functional>
                                   #define int long long
                                            #define inf  1000000007
                                            #define pa pair<int,int>
                                            #define ll long long
                                            #define pal pair<double,double>
                                            #define ppap pair<pa,int>
                                    //  #define PI 3.14159265358979323846
                                            #define paa pair<int,char>
                                            #define  mp make_pair
                                            #define  pb push_back
                                            #define EPS (1e-10)
                                            #define equals(a,b) (fabs((a)-(b))<EPS)
    int dx[8]={0,-1,0,1,1,1,-1,-1};
    int dy[8]={1,0,-1,0,-1,1,1,-1};
                                            using namespace std;
                                   			class pa3{
                                            	public:
                                            	int x,y,z;
                                            	pa3(int x=0,int y=0,int z=0):x(x),y(y),z(z) {}
                                            	bool operator < (const pa3 &p) const{
                                            		if(x!=p.x) return x<p.x;
                                            		if(y!=p.y) return y<p.y;
                                            		 return z<p.z;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                   				bool operator > (const pa3 &p) const{
                                            		if(x!=p.x) return x>p.x;
                                            		if(y!=p.y) return y>p.y;
                                            		 return z>p.z;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa3 &p) const{
                                            		return x==p.x && y==p.y && z==p.z;
                                            	}
                                            		bool operator != (const pa3 &p) const{
                                            			return !( x==p.x && y==p.y && z==p.z);
                                            	}
                                            
                                            };
                                            
                                            class pa4{
                                            	public:
                                            	double x;
                                            	int y,z,w;
                                            	pa4(double x=0,int y=0,int z=0,int w=0):x(x),y(y),z(z),w(w) {}
                                            	bool operator < (const pa4 &p) const{
                                            		if(x!=p.x) return x<p.x;
                                            		if(y!=p.y) return y<p.y;
                                            		if(z!=p.z)return z<p.z;
                                            		return w<p.w;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator > (const pa4 &p) const{
                                            		if(x!=p.x) return x>p.x;
                                            		if(y!=p.y) return y>p.y;
                                            		if(z!=p.z)return z>p.z;
                                            		return w>p.w;
                                            		//return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa4 &p) const{
                                            		return x==p.x && y==p.y && z==p.z &&w==p.w;
                                            	}
                                            		
                                            
                                            };
                                            class pa2{
                                            	public:
                                            	int x,y;
                                            	pa2(int x=0,int y=0):x(x),y(y) {}
                                            	pa2 operator + (pa2 p) {return pa2(x+p.x,y+p.y);}
                                            	pa2 operator - (pa2 p) {return pa2(x-p.x,y-p.y);}
                                            	bool operator < (const pa2 &p) const{
                                            		return y != p.y ? y<p.y: x<p.x;
                                            	}
                                            	bool operator > (const pa2 &p) const{
                                            		return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const pa2 &p) const{
                                            		return abs(x-p.x)==0 && abs(y-p.y)==0;
                                            	}
                                            	bool operator != (const pa2 &p) const{
                                            		return !(abs(x-p.x)==0 && abs(y-p.y)==0);
                                            	}
                                            		
                                            
                                            };
                                            
                                                   #define ppa pair<int,pas>
                                            class Point{
                                            	public:
                                            	double x,y;
                                            	Point(double x=0,double y=0):x(x),y(y) {}
                                            	Point operator + (Point p) {return Point(x+p.x,y+p.y);}
                                            	Point operator - (Point p) {return Point(x-p.x,y-p.y);}
                                            	Point operator * (double a) {return Point(x*a,y*a);}
                                            	Point operator / (double a) {return Point(x/a,y/a);}
                                            	double absv() {return sqrt(norm());}
                                            	double norm() {return x*x+y*y;}
                                            	bool operator < (const Point &p) const{
                                            		return x != p.x ? x<p.x: y<p.y;
                                            	}
                                            	bool operator == (const Point &p) const{
                                            		return fabs(x-p.x)<EPS && fabs(y-p.y)<EPS;
                                            	}
                                            };
                                            typedef Point Vector;
                                     #define pl pair<int,pas>
                                            struct Segment{
                                            Point p1,p2;
                                            };
                                             double dot(Vector a,Vector b){
                                            	return a.x*b.x+a.y*b.y;
                                            }
                                            double cross(Vector a,Vector b){
                                            	return a.x*b.y-a.y*b.x;
                                            }
                                        
                bool parareru(Point a,Point b,Point c,Point d){
                //	if(abs(cross(a-b,d-c))<EPS)cout<<"dd "<<cross(a-b,d-c)<<endl;
                	return abs(cross(a-b,d-c))<EPS;
                }
                double distance_ls_p(Point a, Point b, Point c) {
                  if ( dot(b-a, c-a) < EPS ) return (c-a).absv();
                  if ( dot(a-b, c-b) < EPS ) return (c-b).absv();
                  return abs(cross(b-a, c-a)) / (b-a).absv();
                }
                bool is_intersected_ls(Segment a,Segment b) {
                	if(a.p1==b.p1||a.p2==b.p1||a.p1==b.p2||a.p2==b.p2) return false;
                	if(parareru((a.p2),(a.p1),(a.p1),(b.p2))&&parareru((a.p2),(a.p1),(a.p1),(b.p1))){
                //		cout<<"sss"<<endl;
                		if(dot(a.p1-b.p1,a.p1-b.p2)<EPS) return true;
                		if(dot(a.p2-b.p1,a.p2-b.p2)<EPS) return true;
                		if(dot(a.p1-b.p1,a.p2-b.p1)<EPS) return true;
                		if(dot(a.p1-b.p2,a.p2-b.p2)<EPS) return true;
                		return false;
                	}
                  else return ( cross(a.p2-a.p1, b.p1-a.p1) * cross(a.p2-a.p1, b.p2-a.p1) < EPS ) && ( cross(b.p2-b.p1, a.p1-b.p1) * cross(b.p2-b.p1, a.p2-b.p1) < EPS );
                }
                 
                double segment_dis(Segment a,Segment b){
                	if(is_intersected_ls(a,b))return 0;
                	double r=distance_ls_p(a.p1, a.p2, b.p1);
                	r=min(r,distance_ls_p(a.p1, a.p2, b.p2));
                	r=min(r,distance_ls_p(b.p1, b.p2, a.p2));
                	r=min(r,distance_ls_p(b.p1, b.p2, a.p1));
                	return r;
                }
                Point intersection_ls(Segment a, Segment b) {
                  Point ba = b.p2-b.p1;
                  double d1 = abs(cross(ba, a.p1-b.p1));
                  double d2 = abs(cross(ba, a.p2-b.p1));
                  double t = d1 / (d1 + d2);
                 
                  return a.p1 + (a.p2-a.p1) * t;
                }
                 
                                string itos( int i ) {
                                ostringstream s ;
                                s << i ;
                                return s.str() ;
                                }
                                 
                                int gcd(int v,int b){
                                	if(v>b) return gcd(b,v);
                                	if(v==b) return b;
                                	if(b%v==0) return v;
                                	return gcd(v,b%v);
                                }
                 
                                double distans(double x1,double y1,double x2,double y2){
                                	double rr=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
                                	return sqrt(rr);
                                	
                                }
                                int mod;
                                
                int pr[500010];
                int inv[500010];
                
                int beki(int wa,int rr,int warukazu){
                	if(rr==0) return 1%warukazu;
                	if(rr==1) return wa%warukazu;
                	if(rr%2==1) return (beki(wa,rr-1,warukazu)*wa)%warukazu;
                	int zx=beki(wa,rr/2,warukazu);
                	return (zx*zx)%warukazu;
                }
    double bekid(double w,int r){
    	if(r==0) return 1.0;
    	if(r==1) return w;
    	if(r%2) return bekid(w,r-1)*w;
    	double f=bekid(w,r/2);
    	return f*f;
    }
                
    			int comb(int nn,int rr){
    				int r=pr[nn]*inv[rr];
    				r%=mod;
    				r*=inv[nn-rr];
    				r%=mod;
    				return r;
    			}
                
                void gya(int ert){
                	pr[0]=1;
                	for(int i=1;i<ert;i++){
                		pr[i]=(pr[i-1]*i)%mod;
                	}
                	for(int i=0;i<ert;i++) inv[i]=beki(pr[i],mod-2,mod);
                	
                }
                
              //   cin.tie(0);
    		//	ios::sync_with_stdio(false);
    			//priority_queue<pa3,vector<pa3>,greater<pa3>> pq;            
                 //sort(ve.begin(),ve.end(),greater<int>());
                                         //----------------kokomade tenpure------------
                //vector<double> ans(100000000),ans2(100000000)
    deque<pa3> d1,d2;  
    deque<pa3> d3,d4;       
    int l[100020],r[100020];
    vector<pa3> ve;
    bool sumi[100020]={0};
    signed main(){
     
    	       cin.tie(0);
    			ios::sync_with_stdio(false);
    int n,a,b,k;
    cin>>n;
    //	cout<<ans<<endl;
    //	cout<<ans<<endl;
    	for(int i=0;i<n;i++)cin>>l[i]>>r[i];
    	
    	for(int i=0;i<n;i++){
    				ve.pb((pa3){l[i],r[i],i});
    	}
    	sort(ve.begin(),ve.end());
    	for(int i=0;i<n;i++){
    		d3.pb(ve[i]);
    	}
    	ve.clear();
    	for(int i=0;i<n;i++){
    				ve.pb((pa3){r[i],l[i],i});
    	}
    	sort(ve.begin(),ve.end());
    	for(int i=0;i<n;i++){
    		swap(ve[i].x,ve[i].y);
    	}
    	for(int i=0;i<n;i++){
    		d4.pb(ve[i]);
    	}
    	
    	int ans=0;
    	int it=0;
     	d1=d3,d2=d4;
    	for(int i=0;i<n;i++){
    	
    		int ko1=-1,dis1,ko2=-1,dis2;
    		
    		pa3 z=d1.back();
    		
    		while(sumi[z.z]){
    			d1.pop_back();
    			
    			z=d1.back();
    		}
    		if(it<z.x){
    			ko1=z.z;
    			dis1=z.x-it;
    		}
    		
    		z=d2.front();
    		
    		while(sumi[z.z]){
    			d2.pop_front();
    			
    			z=d2.front();
    		}
    	
    		if(it>z.y){
    			ko2=z.z;
    			dis2=it-z.y;
    		}
    	
    		if(ko1==-1 && ko2==-1){
    			//ans+=abs(it);
    			break;
    		//	return 0;
    		}
    		else if(ko1==-1){
    			sumi[ko2]=1;
    			ans+=dis2;
    			it=r[ko2];
    		}
    		else if(ko2==-1){
    			sumi[ko1]=1;
    			ans+=dis1;
    			it=l[ko1];
    		}
    		else{
    			if(dis2>=dis1 || i==0){
    				sumi[ko2]=1;
    			ans+=dis2;
    			it=r[ko2];
    			}
    			else{
    			sumi[ko1]=1;
    			ans+=dis1;
    			it=l[ko1];
    			}
    		}
    //		cout<<it<<endl;
    		
    		
    	}
    	ans+=abs(it);
    	//cout<<ans<<endl;
    		d1=d3,d2=d4;
    	for(int i=0;i<=n;i++)sumi[i]=0;
    	int ans2=0;
    	it=0;
     	
    	
    	for(int i=0;i<n;i++){
    	
    		int ko1=-1,dis1,ko2=-1,dis2;
    		
    		pa3 z=d1.back();
    		
    		while(sumi[z.z]){
    			d1.pop_back();
    			
    			z=d1.back();
    		}
    		if(it<z.x){
    			ko1=z.z;
    			dis1=z.x-it;
    		}
    	//	cout<<" "<<ko1<<" "<<dis1<<endl;
    		z=d2.front();
    		
    		while(sumi[z.z]){
    			d2.pop_front();
    			
    			z=d2.front();
    		}
    	
    		if(it>z.y){
    			ko2=z.z;
    			dis2=it-z.y;
    		}
    	
    		if(ko1==-1 && ko2==-1){
    		//	ans2+=abs(it);
    			break;
    		//	return 0;
    		}
    		else if(ko1==-1){
    			sumi[ko2]=1;
    			ans2+=dis2;
    			it=r[ko2];
    		}
    		else if(ko2==-1){
    			sumi[ko1]=1;
    			ans2+=dis1;
    			it=l[ko1];
    		}
    		else{
    			if(dis1>=dis2 || i==0){
    				sumi[ko1]=1;
    			ans2+=dis1;
    			it=l[ko1];
    			}
    			else{
    			sumi[ko2]=1;
    			ans2+=dis2;
    			it=r[ko2];
    			}
    		}
    		
    	//	cout<<ko1<<" "<<it<<endl;
    		
    	}
    	ans2+=abs(it);
    	
    	cout<<max(ans,ans2)<<endl;
//    	cout<<ans+abs(it)<<endl;
    	return 0;
            }

Measured memory_bytes: 14780