#include <bits/stdc++.h>
using namespace std;
const int inf = 1000000000;
int main() {
  int N;
  cin >> N;
  vector<int> v(N);
  for (int i = 0; i < N; i++) {
    cin >> v.at(i);
  }
  sort(v.begin(), v.end());
  int i = N - 1;
  while (i != 0) {
    v.at(0) += v.at(i);
    i -= 1;
  }
  cout << (float)v.at(0) / 2 << endl;
}
