ABC315_C.cpp

#include <bits/extc++.h>
using namespace std;
namespace pbds = __gnu_pbds;
using ui = unsigned int;
int main(void) {
  ios::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
  size_t n;
  cin >> n;
  vector<pair<ui, ui>> a(n);
  for (pair<ui, ui>& i : a) cin >> i.first >> i.second;
  sort(a.begin(), a.end());
  ui lsttypemax = 0, thistypemax = a.front().second,
     ans = a.front().second + (thistypemax >> 1);
  for (size_t i = 1; i < n; i++) {
    if (a[i - 1].first != a[i].first)
      lsttypemax = max(lsttypemax, thistypemax), thistypemax = 0;
    thistypemax = max(thistypemax, a[i].second);
    ans =
        max({ans, a[i].second + lsttypemax, a[i].second + (thistypemax >> 1)});
  }
  cout << ans;
  return 0;
}