#include<bits/stdc++.h>
using namespace std;
int main (){
ios::sync_with_stdio(false);
cin.tie(nullptr);
long long n;
cin >> n;
vector<pair<long long,long long>> a(n);
for(int i=0; i<n; i++) cin >> a[i].first >> a[i].second;
sort(a.begin(), a.end());
long long res=0, l=0, tong=0;
for(int r=0; r<n; r++){
tong+=a[r].second;
while (l < r) {
long long sum = tong - a[l].second;
long long amin_new = a[l + 1].first;
long long amax = a[r].first;
if (sum - (amax - amin_new) >= tong - (amax - a[l].first)) {
tong = sum;
l++;
} else break;
}
long long amin = a[l].first;
long long amax = a[r].first;
res = max(res, tong - (amax - amin));
}
cout << res;
}
