#include<bits/stdc++.h>
using namespace std;
struct st{
	int id;
	int v;
	st(int id,int v):id(id),v(v){}
};
bool operator<(st a,st b)
{
	if(a.v != b.v)return a.v < b.v;
	else return a.id < b.id;
}
bool vis[100005];
priority_queue<st> s1,s2;
int n,ans;
int lnum;
bool func(bool must=false)
{
	while(!s1.empty() && vis[s1.top().id])s1.pop();
	while(!s2.empty() && vis[s2.top().id])s2.pop();
	if(s1.empty() || s2.empty())return false;
	st a = s1.top(),b = s2.top();
	s1.pop();
	s2.pop();
	if(a.id != b.id)
	{
		if(must || a.v + b.v > 0)return ans += a.v + b.v,1;
		else return false;
	}
	else
	{
		if(!must)return false;
		else
		{
			while(!s1.empty() && vis[s1.top().id])s1.pop();
			while(!s2.empty() && vis[s2.top().id])s2.pop();
			if(s1.empty() && s2.empty())return false;
			else if(s1.empty())
			{
				st d = s2.top();
				s2.pop();
				ans += a.v + d.v;
				return true;
			}
			else if(s2.empty())
			{
				st c = s1.top();
				s1.pop();
				ans += b.v + c.v;
				return true;
			}
			else
			{
				st c = s1.top();
				st d = s2.top();
				if(a.v + d.v > b.v + c.v)
				{
					s2.pop();
					ans += a.v + d.v;
				}
				else
				{
					s1.pop();
					ans += b.v + c.v;
				}
				return true;
			}
		}
	}
}
signed main()
{
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		int a,b;
		cin>>a>>b;
		if(a >= b)lnum++;
		ans += abs(a - b);
		int v1 = 2 * min(a,b);
		int v2 = 2 * max(a,b);
		v2 = -v2;
		s1.push(st(i,v1));
		s2.push(st(i,v2));
	}
	if(lnum != n && lnum != 0)
	{
		func(true);
	}
	while(func());
	cout<<ans;
}