#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;
const ll mod=1e9+7;
const ll maxn=5e5+5;
const int INF=1e9;
#define ok ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define fi first
#define se second
#define pb push_back
#define ub upper_bound
#define lb lower_bound
#define endl '\n'
int n;
pll arr[maxn], suf[maxn];
ll cur, sum[maxn], ans;
int main() {
ok
cin >> n;
for(int i=1; i<=n; i++) cin >> arr[i].fi >> arr[i].se;
sort(arr+1, arr+n+1);
for(int i=1; i<=n; i++) {
cur+=arr[i].se;
suf[i]={cur-(arr[i].fi-arr[1].fi), i};
sum[i]=cur;
}
for(int i=n-1; i>=1; i--) {
if(suf[i].fi<suf[i+1].fi) {
suf[i]={suf[i+1].fi, suf[i+1].se};
}
}
for(int i=1; i<=n; i++) {
pll now=suf[i];
ans=max(ans, sum[now.se]-sum[i-1]-(arr[now.se].fi-arr[i].fi));
}
cout << ans;
}
