#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> er;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int N;
cin >> N;
vector<er> art(N);
for (int i = 0; i < N; ++i) {
ll A;
int B;
cin >> A >> B;
art[i] = { A, B };
}
sort(art.begin(), art.end());
ll maxScore = 0;
int left = 0;
ll valueSum = 0;
for (int right = 0; right < N; ++right) {
valueSum += art[right].second;
while (left < right && valueSum - (art[right].first - art[left].first) < maxScore) {
valueSum -= art[left].second;
left++;
}
ll score = valueSum - (art[right].first - art[left].first);
maxScore = max(maxScore, score);
}
cout << maxScore << "\n";
return 0;
}
