#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define sz(x) x.size()
#define nl '\n'
#define F first
#define S second
const int N = 1e6 + 1;
const int inf = 1e18;
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n;
cin >>n;
pair<int, int>a[n + 1];
for( int i = 1; i <= n; ++i )
cin >>a[i].F >>a[i].S;
sort(a + 1, a + n + 1);
int ans = 0;
for( int l = 1; l <= n; ++l )
{
int mn = inf, mx = 0, sum = 0;
for( int r = l; r <= n; ++r )
{
mn = min(mn, a[r].F);
mx = max(mx, a[r].F);
sum += a[r].S;
ans = max(ans, sum - mx + mn);
}
}
cout <<ans;
}
