#include<bits/stdc++.h> #define ll long long #define int long long #define maxn 500005 #define fi first #define se second #define sti string using namespace std; pair<int,int> a[maxn]; int n; ll pre[maxn]; signed main () { ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0); cin>>n; for(int i=1;i<=n;i++) cin>>a[i].fi>>a[i].se; sort(a+1,a+n+1); for(int i=1;i<=n;i++) pre[i]=pre[i-1]+a[i].se; ll ans=0; ll Min=4e18; for(int r=1;r<=n;r++){ Min=min(Min,pre[r-1]-a[r].fi); ans=max(ans,(pre[r]-a[r].fi)-Min); } cout<<ans; return 0; }