#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 5e5+5;
int N;
pair<ll,ll> a[maxn];
ll f(int l, int r) {
if (l > r) return 0;
if (l == r) {
return a[l].second;
}
int m = (l+r)/2;
//get max of arrays that go thru mid
ll lmax = 0, lcurr = 0;
for (int i = m; i >= l; i--) {
lcurr += a[i].second;
lmax = max(lmax,lcurr-(a[m].first-a[i].first));
}
ll rmax = 0, rcurr = 0;
for (int i = m + 1; i <= r; i++) {
rcurr += a[i].second;
rmax = max(rmax,rcurr-(a[i].first-a[m].first));
}
return max(lmax+rmax,max(f(l,m),f(m+1,r)));
}
int main()
{
ios_base::sync_with_stdio(false); cin.tie(NULL);
cin >> N;
for (int i = 0; i < N; i++) {
cin >> a[i].first >> a[i].second;
}
sort(a,a+N);
ll ans = f(0,N-1);
cout << ans << '\n';
return 0;
}
