// IN THE NAME OF ALLAH
// YA IMAM REZA
#include<bits/stdc++.h>
using namespace std;
#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define wall cerr << "------------------------------------" << endl
#define pb push_back
#define pob pop_back
#define F first
#define S second
#define all(x) x.begin() , x.end()
#define int ll
#define kids int tm = (tl + tr)>>1; int cl = v<<1; int cr = v<<1|1
#define test int n;cin >> n;while(n--)
#define file freopen("input.txt" , "r" , stdin); freopen("output.txt" , "w" , stdout)
#define debug while(1) cout << "TEST\n"
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#pragma GCC optimize("Ofast")
typedef long long ll;
typedef pair<int , int> pii;
typedef pair<ll , ll> pll;
typedef pair<pii,int> piii;
typedef pair<pll , ll> plll;
const int N = 5e5 + 10;
const int K = 400+10;
const ll mod = 1e9+7;
const ll INF = 1e18+10;
const int P = 31;
const int lg = 25;
const int delta = 30103;
int seg[N << 2];
int la[N << 2];
int n;
int a[N];
int b[N];
vector<pii> vec;
void shift(int v , int tl , int tr) {
seg[v] += la[v];
if(tl != tr) {
la[v << 1] += la[v];
la[v << 1 | 1] += la[v];
}
la[v] = 0;
}
void upd(int v , int tl , int tr , int l , int r , int x) {
shift(v , tl , tr);
if(l > r)
return;
if(tl == l && tr == r) {
la[v] += x;
shift(v , tl , tr);
return;
}
kids;
upd(cl , tl , tm , l , min(tm , r) , x);
upd(cr , tm+1 , tr , max(l , tm+1) , r , x);
seg[v] = max(seg[cl] , seg[cr]);
}
int ask(int v , int tl , int tr , int l , int r) {
shift(v , tl , tr);
if(l > r)
return -INF;
if(tl == l && tr == r)
return seg[v];
kids;
return max(ask(cl , tl , tm , l , min(tm , r)) , ask(cr , tm+1 , tr , max(l , tm+1) , r));
}
void solve() {
cin >> n;
for(int i = 1 ; i <= n ; i++)
cin >> a[i] >> b[i] , vec.pb({a[i] , b[i]});
sort(all(vec));
for(int i = 1 ; i <= n ; i++)
a[i] = vec[i-1].F , b[i] = vec[i-1].S;
int ans = -INF;
for(int i = 1 ; i <= n ; i++) {
// cout << a[i] << " " << b[i] << "\n";
upd(1 , 1 , n , 1 , i , b[i]);
upd(1 , 1 , n , 1 , i-1 , -a[i] + a[i-1]);
ans = max(ans , ask(1 , 1 , n , 1 , i));
}
cout << ans << "\n";
}
signed main()
{
fast;
solve();
}
