#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int N = 1e5 + 5;
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// #ifndef ONLINE_JUDGE
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
// #endif
ll n, cevap = 0;
cin >> n;
vector<pair<ll, ll>> vec(n);
for(int i = 0; i < n; i++)
cin >> vec[i].first >> vec[i].second;
sort(vec.begin(), vec.end());
for(int l = 0; l < n; l++)
{
ll sum = 0, mx = 0, mn = 1e16;
for(int r = l; r < n; r++)
{
sum += vec[r].second;
mn = min(mn, vec[r].first);
mx = max(mx, vec[r].first);
cevap = max(cevap, sum - (mx - mn));
}
}
cout << cevap << '\n';
return 0;
}
