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

int main() {
	cin.tie(0) -> sync_with_stdio(0);
	int n; cin >> n;
	vector<pair<ll, ll>> a(n);
	for(auto& i: a) cin >> i.first >> i.second;
	sort(a.begin(), a.end(), [&](auto x, auto y){
		return x.first - x.second < y.first - y.second;
	});
	ll sum_b = 0;
	for(int i = 0; i < n; i++) sum_b += a[i].second;
	ll sum_a = 0, ans = sum_b;
	for(int i = 0; i < n; i++){
		sum_a += a[i].first;
		sum_b -= a[i].second;
		ans = min(ans, max(sum_a, sum_b));
	}
	cout << ans << endl;
}