#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int N = 1e5 + 5;
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
// #ifndef ONLINE_JUDGE
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
// #endif
ll n;
cin >> n;
vector<pair<ll, ll>> vec(n + 1);
vector<ll> prefix(n + 1);
for(int i = 1; i <= n; i++)
cin >> vec[i].first >> vec[i].second;
sort(vec.begin() + 1, vec.end());
for(int i = 1; i <= n; i++)
{
prefix[i] = prefix[i - 1];
prefix[i] += vec[i].second;
}
ll l = 1, mn = vec[1].first, cevap = vec[1].second;
for(int r = 2; r <= n; r++)
{
while(l < r and vec[r].first - mn > prefix[r - 1] - prefix[l - 1])
{
l++;
mn = vec[l].first;
}
cevap = max(cevap, (prefix[r] - prefix[l - 1]) - (vec[r].first - mn));
}
cout << cevap << '\n';
return 0;
}
