/*
written by sim_ple
*/
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define N 500005
#define itn int
#define all(x) x.begin() , x.end()
int sz[N] , vl[N];
int b[N];
int n , ans = 0;
void f(int idx){
if(idx == n + 1){
int sum = 0 , mn = INT_MAX , mx = 0;
for(int i = 1; i <= n; i++){
if(b[i]){
sum += vl[i];
mx = max(mx , sz[i]);
mn = min(mn ,sz[i]);
}
}
if(mn == INT_MAX){
return;
}
ans = max(ans , sum + mn - mx);
return;
}
b[idx] = 0;
f(idx + 1);
b[idx] = 1;
f(idx + 1);
}
void solve(){
cin >> n;
for(int i = 1; i <= n; i++){
cin >> sz[i] >> vl[i];
}
f(1);
cout << ans << endl;
}
int32_t main() {
ios::sync_with_stdio(false);cin.tie(nullptr);
int t = 1;
//cin >> t;
while(t--) solve();
}
