#include <bits/stdc++.h> #pragma GCC optimize("O3") #define FOR(i, x, y) for (int i = x; i < y; i++) typedef long long ll; using namespace std; pair<ll, ll> a[500001]; ll pref[500001]; int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); ll n; cin >> n; FOR(i, 1, n + 1) cin >> a[i].first >> a[i].second; sort(a + 1, a + n + 1); pref[0] = 0; FOR(i, 1, n + 1) pref[i] = pref[i - 1] + a[i].second; ll l = 1; ll ans = a[1].second; FOR(i, 2, n + 1) { ll diff = a[i].first - a[i - 1].first + a[i].second; while (diff < 0) diff += a[l++].second; ans = max(ans, (pref[i] - pref[l - 1]) - (a[i].first - a[l].first)); } cout << ans; return 0; }