#ifdef ONLINE_JUDGE
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#endif
#include <bits/stdc++.h>
#define ll long long int
#define speed ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define TxtIO freopen("lol.in","r",stdin); freopen("lol.txt","w",stdout);
#define forn(i,n) for(int i=0;i<n;i++)
#define pb push_back
using namespace std;
void solve(){
ll n;
cin>>n;
vector <pair<ll,ll>> v(n);
forn(i,n) cin>>v[i].first>>v[i].second;
sort(v.begin(),v.end(),greater<pair<ll,ll>>());
ll ans=0;
for(int i=0;i<n;i++){
ll sum=0,max1=0,min1=1e18;
for(int j=i;j<n;j++){
sum+=v[j].second;
max1=max(max1,v[j].first);
min1=min(min1,v[j].first);
ans=max(ans,sum-(max1-min1));
}
}
cout<<ans;
}
signed main(){
speed;
int t=1;
while(t--){
solve();
}
}
