#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define ll long long
//#define int long long
const ll mod=998244353;
const int mxsz=2e5+4;
const ll inf =1e9+4;
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n;
cin>>n;
pair<ll,ll>a[n];
for (int i=0;i<n;i++){
cin>>a[i].first>>a[i].second;
}
vector<ll>ans;ll c=0;
for (int i=1;i<(1<<n);i++){
vector<ll>cur;
ll sum=0;ll mn=inf,mx=0;
for (int j=0;j<n;j++){
if ((1<<j)&i){
sum+=a[j].second;
mn=min(mn,a[j].first);
mx=max(mx,a[j].first);
}
}
c=max(c,sum-(mx-mn));
}
cout<<c<<endl;
return 0;
}
