#include <bits/stdc++.h> #define ll long long #define endl '\n' using namespace std; const int N = 500005; pair<ll,ll>ar[N+3]; int n; int main(){ ios::sync_with_stdio(0); cin.tie(0); cin>>n; for(int i=1;i<=n;i++){ ll x,y;cin>>x>>y; ar[i]={x,y}; } sort(ar+1,ar+n+1); for(int i=1;i<=n;i++){ ar[i].second+=ar[i-1].second; } ll mx=ar[n].second-ar[n].first,ans=-1; for(int i=n-1;i>=1;i--){ ans=max(ans,mx-ar[i-1].second+ar[i].first); mx=max(mx,ar[i].second-ar[i].first); } cout<<ans; } /* 3 2 3 11 2 4 5 */