#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N=5e5+5;
int n,sum,ans,pos,mn=1e16,mx;
pair <int,int> a[N];
deque <pair <int,int>> dq;
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n;
for(int i=1;i<=n;i++) cin >> a[i].first >> a[i].second;
sort(a+1,a+1+n);
for(int i=1;i<=n;i++){
sum+=a[i].second;
mn=min(mn,a[i].first);
mx=max(mx,a[i].first);
ans=max(ans,sum-(mx-mn));
while(!dq.empty() && sum-(mx-mn)<0){
sum-=dq.front().second;
dq.pop_front();
mn=(!dq.empty()?dq.front().first:a[i].first);
ans=max(ans,sum-(mx-mn));
}
ans=max(ans,sum-(mx-mn));
dq.push_back({a[i].first,a[i].second});
}
cout << ans;
}
