#include<bits/stdc++.h> #define int long long using namespace std; int a[500005], b[500005]; signed main() { ios_base::sync_with_stdio(false); cin.tie(0); int n; cin>>n; vector<pair<int, int>> c(n); for(int i = 0; i < n; i++) cin>>c[i].first>>c[i].second; sort(c.begin(), c.end()); for(int i = 0; i < n; i++){ a[i+1] = c[i].first; b[i+1] = c[i].second; } for(int i = 1; i <= n; i++) b[i] += b[i-1]; int maximum = -1e18, ans = -1e18; for(int i = 1; i <= n; i++){ maximum = max(maximum, -b[i-1] + a[i]); ans = max(ans, b[i] - a[i] + maximum); } cout<<ans; }