#include <bits/stdc++.h> using namespace std; #define ll long long int #define oo 1e15 + 9 #define pii pair<ll, ll> int main(){ int n; cin >> n; pii arr[n]; for (int i = 0; i < n; i++) { cin >> arr[i].first >> arr[i].second; } sort(arr, arr + n); ll PreSum[n + 1]; PreSum[0] = 0; for (int i = 1; i <= n; i++) { PreSum[i] = PreSum[i - 1] + arr[i - 1].second; } multiset<ll> s; for (int i = 1; i <= n; i++) { s.insert(PreSum[i] - arr[i - 1].first); } ll ans = 0; for (int i = 0; i < n; i++) { ll b = *prev(s.end()); ans = max(ans, b - PreSum[i] + arr[i].first); s.erase(s.find(PreSum[i + 1] - arr[i].first)); } cout << ans; }