//tavakol bar khoda #include <bits/stdc++.h> using namespace std; typedef long long ll; typedef long double ld; const int MAXN = (int)5e5 + 7; const int MOD = (int)1e9 + 7; const int infint = (int)1e8 + 3; const ll inf = (ll)1e18; ll n, part[MAXN]; pair<ll, ll> P[MAXN]; int main() { ios::sync_with_stdio(false); cin.tie(0); cout.tie(0); cin >> n; for (int i = 0; i < n; i++) cin >> P[i].first >> P[i].second; sort(P, P + n); part[0] = P[0].second; for (int i = 1; i < n; i++) part[i] = part[i - 1] + P[i].second; ll ans = 0, mn = 0; for (int i = 0; i < n; i++) { if(i == 0) mn = -P[0].first; else mn = min(mn, part[i - 1] - P[i].first); ans = max(ans, part[i] - P[i].first - mn); } cout << ans; }