#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5;
typedef long long ll;
int n,a[N],b[N],m,mxb,mnb,mxa,mna,pr[N],su[N];
ll ans,res;
bool v[N],fg,g[N];
struct va{
	int v,id;
	bool operator <(const va a)const{return v<a.v;}
}w[N<<1];
int main(){
	scanf("%d",&n);
	for(int i=1;i<=n;++i){
		scanf("%d%d",&a[i],&b[i]);
		w[++m]={a[i],i},w[++m]={b[i],i};
	}
	sort(w+1,w+m+1);
	for(int i=1;i<=n;++i){
		ans-=w[i].v;
		int x=w[i].id;
		if(v[x])fg=true;
		if(w[i].v==a[x])g[x]=true;
		v[x]=true;
	}
	for(int i=n+1;i<=m;++i)ans+=w[i].v;
	if(fg)return printf("%lld\n",ans),0;
	for(int i=1;i<=n;++i){
		pr[i]=pr[i-1];
		if(g[i])pr[i]=max(pr[i],a[i]);
		else pr[i]=max(pr[i],b[i]);
	}
	for(int i=n;i;--i){
		su[i]=su[i+1];
		if(g[i])su[i]=max(su[i],a[i]);
		else su[i]=max(su[i],b[i]);
	}
	for(int i=1;i<=n;++i){
		if(g[i])res=max(res,ans-2ll*b[i]+2ll*max(pr[i-1],su[i+1]));
		else res=max(res,ans-2ll*a[i]+2ll*max(pr[i-1],su[i+1]));
	}
	printf("%lld\n",res);
	return 0;
}