#include <bits/stdc++.h>
#define startt ios_base::sync_with_stdio(false);cin.tie(0);
typedef unsigned long long ull;
typedef long long ll;
using namespace std;
#define FOR(n) for(int i=0;i<n;i++)
#define vt vector
#define vint vector<int>
#define all(v) v.begin(), v.end()
#define sz(a) (int)a.size()
#define MOD 1000000007
#define MOD2 998244353
#define MX 1000000000
#define NMAX 100005
#define MXL 1000000000000000000
#define PI 3.14159265
#define pb push_back
#define pf push_front
#define sc second
#define endl '\n'
#define fr first
#define int ll
#define ld long double
int ceildiv(int one, int two) {
if (one % two == 0) {return one / two;}
else {return one / two + 1;}
} int power(int n, int pow, int m) {
if (pow == 0) return 1;
if (pow % 2 == 0) {
ll x = power(n, pow / 2, m);
return (x * x) % m;
}
else return (power(n, pow - 1, m) * n) % m;
} int gcd(int a, int b) {
if (!b)return a;
return gcd(b, a % b);
} int factorial(int n, int mod) {
if (n > 1)
return (n * factorial(n - 1, mod)) % mod;
else
return 1;
} int lcm(int a, int b) {
return (a * b) / gcd(a, b);
} vector<int> read(int n) {vector<int> a; for (int i = 0; i < n; i++) { int x; cin >> x; a.pb(x);} return a;}
void solve() {
int n;
cin >> n;
pair<int, int> a[n + 1];
for (int i = 0; i < n; i++)
{
cin >> a[i].fr >> a[i].sc;
}
vint pref;
pref.pb(0);
sort(a, a + n);
for (int i = 0; i < n; i++)
{
pref.pb(pref.back() + a[i].sc);
}
int best = 0;
for (int s = 1; s <= n; s++)
{
for (int j = 0; j < n - s + 1; j++)
{
best = max(best, pref[j + s] - pref[j] - (a[j + s - 1].fr - a[j].fr));
}
}
cout << best << endl;
}
int32_t main() {
//#ifndef ONLINE_JUDGE
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
//#endif
solve();
}
