#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define ull unsigned long long
#define fi first
#define se second
#define ld long double
ll n, dp[5005][5005], pref[5005];
pair<ll, ll>arr[5005];
ll solve(ll l, ll r){
if(l > r) return 0;
if(dp[l][r]!=-1) return dp[l][r];
ll sums=(pref[r]-pref[l-1])-(arr[r].fi-arr[l].fi);
ll ans=sums;
ans=max(ans, solve(l+1, r));
ans=max(ans, solve(l, r-1));
return dp[l][r]=ans;
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
memset(dp, -1, sizeof dp);
for(int i=1;i<=n;++i){
cin >> arr[i].fi >> arr[i].se;
}
sort(arr+1, arr+1+n);
for(int i=1;i<=n;++i) pref[i]=pref[i-1]+arr[i].se;
cout << solve(1, n) << '\n';
}
