#include <bits/stdc++.h>
using namespace std;
#define int long long
#define all(x) x.begin(), x.end()
#define inf (int)3e18
#define ff first
#define ss second
using vi = vector<int>;
using vii = vector<pair<int, int>>;
using vvi = vector<vector<int>>;
using pii = pair<int, int>;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
const int MAX = 20;
int a[MAX], b[MAX];
void solve()
{
int n;
cin >> n;
for (int i = 0; i < n; i++)
cin >> a[i] >> b[i];
int ans = -inf;
for (int mask = 1; mask < (1 << n); mask++)
{
int S = 0;
int mx = -inf, mn = inf;
for (int i = 0; i < n; i++)
{
if (mask & (1 << i))
{
mx = max(mx, a[i]);
mn = min(mn, a[i]);
S += b[i];
}
}
ans = max(ans, S - (mx - mn));
}
cout << ans;
}
signed main()
{
ios::sync_with_stdio(0);
cin.tie(0);
int tt = 1;
// cin >> tt;
while (tt--)
solve();
}
