#include <bits/stdc++.h>
#define int long long
#define fi first
#define se second
using namespace std;
const int N = 5e5 + 11;
pair<int, int> a[N];
int pref[N];
int cost(int i, int j) {
int sum = pref[j] - pref[i - 1];
int mx = a[j].fi, mn = a[i].fi;
return sum - (mx - mn);
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n;
cin >> n;
for(int i = 1; i <= n; i++){
cin>>a[i].fi>>a[i].se;
}
sort(a + 1, a + 1 + n);
for(int i = 1; i <= n; i++){
pref[i] = pref[i - 1] + a[i].se;
}
int res = 0;
for(int i = 1; i <= n; i++){
int l = i, r = n, ans = 0;
for(int j = 1; j <= 1000; j++){
int m1 = l + (r - l) / 3;
int m2 = r - (r - l) / 3;
ans = max({ans, cost(i, m1), cost(i, m2)});
if(cost(i, m1) > cost(i, m2))l = m1;
else r = m2;
}
for(int j = -500; j <= 500; j++){
if((l + j) >= i && (l + j) <= n) {
if(cost(i, l + j) > ans)ans = cost(i, l + j);
}
}
res = max(res, ans);
}
cout << res << '\n';
}
