Problem:       
    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

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int main(int argc, char **argv) {
  ios_base::sync_with_stdio(false), cin.tie(0);
  double TUX, FOO, BAR, BAZ, QUZ, PUR;
  cin >> TUX;
  FOO = 0;
  BAR = 0;
  BAZ = 0;
  QUZ = 1;
  while (TUX--) {
    cin >> PUR;
    FOO = FOO + PUR;
    BAR = BAR + 1;
    if (max(FOO * QUZ, BAR * BAZ) == FOO * QUZ) {
      BAZ = FOO;
      QUZ = BAR;
    }
  }
  cout << setprecision(6) << fixed << BAZ / QUZ << '\n';
  return 0;
}