#include <bits/stdc++.h>
using namespace std;
//typedef long long ll;
///typedef unsigned long long ull;
//typedef pair<long long,long long> pl;
#define all(s) s.begin(),s.end()
#define F first
#define S second
#define sz(a) a.size()
#define int long long
typedef pair<int,int> pi;
//const ll mod = 998244353;
//const ll mod1 = 1e9+7;
//const ll INF = 1e18;
const int N = 100200;
const int inf = 1e18+200;
int n;
pi a[N*5];
int p[N*5];
pi b[N*5];
int ans=0;
void solve() {
cin>>n;
for(int i=1;i<=n;++i) {
cin>>a[i].F>>a[i].S;
}
sort(a+1,a+1+n);
for(int i=1;i<=n;++i) {
p[i]=p[i-1]+a[i].S;
}
for(int i=1,j=1;i<=n;++i) {
int s1=p[i]-p[j-1]-(a[i].F-a[j].F);
int s2=p[i]-p[i-1];
if(s2>s1) {
j=i;
}
ans=max(ans,p[i]-p[j-1]-(a[i].F-a[j].F));
}
cout<<ans<<'\n';
}
signed main() {
ios_base::sync_with_stdio(0) , cin.tie(0) , cout.tie(0);
int T=1;
//cin>>T;
while(T--) {
solve();
}
return 0;
}
