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;
static int TUX = 0, PUR, FOO = 0, BAR = 0, BAZ = 0, QUZ = 1;
static bool IT;
int main() {
  scanf("%d", &TUX);
  for (; !((TUX == 0)); TUX--) {
    scanf("%d", &PUR);
    FOO += PUR;
    BAR++;
    IT = (((FOO * QUZ)) > ((BAR * BAZ)) ? ((FOO * QUZ)) : ((BAR * BAZ))) ==
         (FOO * QUZ);
    if (IT) {
      BAZ = FOO;
      QUZ = BAR;
    }
  }
  printf("%f", BAZ / (double)QUZ);
  return 0;
}