#include<iostream>
#include<vector>
#include<algorithm>
#include<set>
#include<map>
#include<utility>
#define int long long
#define INF 1000000000000000000
#define pii pair<long long, long long>
using namespace std;
signed main() {
ios::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<pii>v(n);
for(int i = 0 ; i < n ; i++) cin >> v[i].first >> v[i].second;
sort(v.begin(), v.end());
vector<int>psum(n);
psum[0] = v[0].second;
for (int i = 1 ; i < n ; i++) psum[i] = psum[i-1] + v[i].second;
int ans = 0;
for (int i = 0 ; i < n ; i++) {
//cout << psum[i] << " ";
for (int j = i ; j < n ; j++) {
int t;
if (i == 0) t = psum[j] - (v[j].first - v[i].first);
else t = (psum[j] - psum[i-1]) - (v[j].first - v[i].first);
//cout << t << " ";
ans = max(ans, t);
}
//out << "\n";
}
cout << ans << "\n";
}
