#include<iostream>
#include<algorithm>
using namespace std;

#define int long long
const int MAXN = 1e5 + 5;
int n;
struct node{
	int a, b;
}t[MAXN];

void solve(){
	cin >> n;
	for(int i = 1;i <= n;i ++){
		cin >> t[i].a >> t[i].b;
	}
	sort(t + 1, t + n + 1, [](node x, node y){
		bool f1 = x.a < x.b;
		bool f2 = y.a < y.b;
		if(f1 != f2) return f1 > f2;
		if(f1) return x.a < y.a;
		return x.b > y.b;
	});
	int sum = 0, ans = 0;
	for(int i = 1;i <= n;i ++){
		sum += t[i].a;
		ans = max(ans, sum) + t[i].b;
	}
	cout << ans << '\n';
}

signed main(){
	freopen("service.in", "r", stdin);
	freopen("service.out", "w", stdout);
//	int t; cin >> t;
//	while(t --){
		solve();
//	}
	return 0;
}