#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define dbg(...) 42
#endif
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<pair<int64_t, int64_t>> a(n);
for (int i = 0; i < n; i++) {
cin >> a[i].first >> a[i].second;
}
sort(a.begin(), a.end());
int64_t sum = 0, ans = 0;
for (int l = 0, r = 0; r < n; r++) {
sum = sum + a[r].second;
ans = max(ans, sum - (a[r].first - a[l].first));
while (l + 1 <= r && sum - a[l].second - (a[r].first - a[l + 1].first) >= ans) {
ans = sum - a[l].second - (a[r].first - a[l + 1].first);
sum -= a[l].second;
l++;
}
}
cout << ans << '\n';
return 0;
}
