#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
const long long INF = (1e9);
const long long N = 1e5 + 5;
const long long M = 998244353;
void solve() {
  long long n;
  cin >> n;
  double ans = 0;
  double sm = 0;
  for (long long i = 1; i <= n; i++) {
    long long x;
    cin >> x;
    sm += x;
    double bb = sm / (1.0 * i);
    if (bb > ans) {
      ans = bb;
    }
  }
  cout << fixed << setprecision(6) << ans << endl;
}
int32_t main() {
  long long t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
