#include <bits/stdc++.h>
using namespace std;
#define int long long
int32_t main() {
int n; cin >> n;
vector<pair<int, int>> a(n);
for (int i = 0; i < n; i++) {
cin >> a[i].first >> a[i].second;
}
sort(a.begin(), a.end());
vector<int> p(n, a[0].second);
for (int i = 1; i < n; i++) {
p[i] = p[i - 1] + a[i].second;
}
int ans = 0;
for (int i = 0; i < n; i++) {
for (int j = i; j < n; j++) {
int cur = 0;
cur += p[j];
cur -= (i > 0 ? p[i - 1] : 0);
cur -= a[j].first - a[i].first;
ans = max(ans, cur);
}
}
cout << ans << '\n';
}
