      
    HAI  
    I HAS A TUX  
    GIMMEH TUX  
    I HAS A FOO ITS 0  
    I HAS A BAR ITS 0  
    I HAS A BAZ ITS 0  
    I HAS A QUZ ITS 1  
    TUX IS NOW A NUMBR  
    IM IN YR LOOP NERFIN YR TUX TIL BOTH SAEM TUX AN 0  
    I HAS A PUR  
    GIMMEH PUR  
    PUR IS NOW A NUMBR  
    FOO R SUM OF FOO AN PUR  
    BAR R SUM OF BAR AN 1  
    BOTH SAEM BIGGR OF PRODUKT OF FOO AN QUZ AN PRODUKT OF BAR BAZ AN PRODUKT OF FOO AN QUZ  
    O RLY?  
    YA RLY  
    BAZ R FOO  
    QUZ R BAR  
    OIC  
    IM OUTTA YR LOOP  
    BAZ IS NOW A NUMBAR  
    VISIBLE SMOOSH QUOSHUNT OF BAZ QUZ  
    KTHXBYE  
    

Input

The input contains between 1 and 10 lines, i-th line contains an integer number xi (0 ≤ xi ≤ 9).

Output

Output a single real number. The answer is considered to be correct if its absolute or relative error does not exceed 10 - 4.

Examples

Input

3
0
1
1


Output

0.666667
#include <bits/stdc++.h>
int asalmi(int x) {
  int i, k = (int)sqrt(x);
  for (i = 2; i <= k; i++)
    if (x % i == 0) return 0;
  return 1;
}
int ters(int x) {
  int bas = 0, t = x, i, k = 0;
  while (t) {
    bas++;
    t /= 10;
  }
  for (i = 1; i <= bas; i++) {
    k *= 10;
    k += x % 10;
    x /= 10;
  }
  return k;
}
using namespace std;
long long m, n;
void read() {}
void solve() {
  int n, i;
  double x, res = 0., k = 0.;
  cin >> n;
  i = n;
  while (i--) {
    cin >> x;
    res += x;
    k = ((k > res / (n - i)) ? k : res / (n - i));
  }
  if (!n)
    cout << "0" << endl;
  else
    cout << k << endl;
}
void write() { int i, j; }
int main() {
  read();
  solve();
  write();
  return 0;
}
