#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vi vector<int>
#define vl vector<ll>
#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define all(v) v.begin(), v.end()
#define SZ(x) ((int)((x).size()))
#define pow2(x) ((ll)(x) * (x))
const ll mod = 1e9 + 7;
const int INF = 1e9 + 5; // 998244353
const ll INFF = 1e18 + 5;
// Super is the cutest girl
void solve()
{
int n;
cin >> n;
vector<pll> v(n);
for (int i = 0; i < n; i++)
{
cin >> v[i].fi >> v[i].se;
}
sort(all(v));
vl pref(n + 1);
for (int i = 0; i < n; i++)
{
pref[i + 1] = pref[i] + v[i].se;
}
ll ans = 0;
ll curr = 0;
int l = 0;
for (int i = 0; i < n; i++)
{
curr += v[i].se;
ll xd = curr - (v[i].fi - v[l].fi);
if (xd < ans)
{
}
ans = max(ans, curr - (v[i].fi - v[l].fi));
}
for (int i = 0; i < n; i++)
{
for (int j = i; j < n; j++)
{
ans = max(ans, pref[j + 1] - pref[i] - (v[j].fi - v[i].fi));
}
}
cout << ans << '\n';
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
// freopen("input.txt","r",stdin);
// freopen("output.txt","w",stdout);
// int t; cin >> t; while(t--)
solve();
}
