#include <bits/stdc++.h>
using namespace std;
#define ll long long

struct node{
	ll a,b;
}t[2100000];

ll n;
ll n1,n2;

bool cmp(node aa,node bb){
	ll a1=(aa.a<aa.b),b1=(bb.a<bb.b);
	if (aa.a>aa.b) a1=-1;
	if (bb.a>bb.b) b1=-1;
	if(a1!=b1) return a1>b1;
	else if (a1>=0) return aa.a<bb.a;
	else return aa.b>bb.b;
}

int main(){
	freopen("service.in","r",stdin);
	freopen("service.out","w",stdout);
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>t[i].a>>t[i].b;
	}
	sort(t+1,t+n+1,cmp);
	for(int i=1;i<=n;i++){
		n1+=t[i].a;
		n2=max(n1,n2)+t[i].b;
	}
	cout<<n2<<'\n';
	return 0;
}