#include <bits/stdc++.h> #define IOS ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0) #define int long long using namespace std; signed main() { IOS; int n, ans = 0; cin >> n; pair <int, int> pr[n]; int arr[n]; for (int i = 0; i < n; i++) cin >> pr[i].first >> pr[i].second; sort(pr, pr+n); arr[0] = pr[0].second; ans = arr[0]; for (int i = 1; i < n; i++) { int sum = arr[i-1]+pr[i-1].first+pr[i].second; arr[i] = max(pr[i].second, sum-pr[i].first); ans = max(ans, arr[i]); } cout << ans; return 0; }