#include <bits/stdc++.h> #define ll long long using namespace std; int main() { ios_base::sync_with_stdio(0); cin.tie(nullptr); int n; cin >> n; vector<ll> a(n), b(n); vector<pair<ll, int>> v; for (int i = 0; i < n; i++) { cin >> a[i] >> b[i]; v.push_back({b[i] - a[i], i}); } sort(v.rbegin(), v.rend()); ll ans = 0, sum = 0, mx = -1e18, mn = 1e18; for (int i = 0; i < n; i++) { sum += b[v[i].second]; mx = max(mx, a[v[i].second]); mn = min(mn, a[v[i].second]); ans = max(ans, sum - (mx - mn)); } cout << ans; }