B. Getting an A（水题）

B. Getting an A

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

Translator's note: in Russia's most widespread grading system, there are four grades: 5, 4, 3, 2, the higher the better, roughly corresponding to A, B, C and F respectively in American grading system.

The term is coming to an end and students start thinking about their grades. Today, a professor told his students that the grades for his course would be given out automatically  — he would calculate the simple average (arithmetic mean) of all grades given out for lab works this term and round to the nearest integer. The rounding would be done in favour of the student — $4.5$ would be rounded up to $5$ (as in example 3), but $4.4$ would be rounded down to $4$.

This does not bode well for Vasya who didn't think those lab works would influence anything, so he may receive a grade worse than $5$(maybe even the dreaded $2$). However, the professor allowed him to redo some of his works of Vasya's choosing to increase his average grade. Vasya wants to redo as as few lab works as possible in order to get $5$ for the course. Of course, Vasya will get $5$ for the lab works he chooses to redo.

Help Vasya — calculate the minimum amount of lab works Vasya has to redo.

Input

The first line contains a single integer $n$ — the number of Vasya's grades ($1\le n\le 100$).

The second line contains $n$ integers from $2$ to $5$ — Vasya's grades for his lab works.

Output

Output a single integer — the minimum amount of lab works that Vasya has to redo. It can be shown that Vasya can always redo enough lab works to get a $5$.

Examples

input

Copy

3
4 4 4

output

Copy

2

input

Copy

4
5 4 5 5

output

Copy

0

input

Copy

4
5 3 3 5

output

Copy

1

Note

In the first sample, it is enough to redo two lab works to make two $4$s into $5$s.

In the second sample, Vasya's average is already $4.75$ so he doesn't have to redo anything to get a $5$.

In the second sample Vasya has to redo one lab work to get rid of one of the $3$s, that will make the average exactly $4.5$ so the final grade would be $5$

题意：给出n，和n个数 ai （2<=ai<=5）,你可以将其中任意一个不为5的数改成5.求出这些数的平均值（四舍五入），问，最少改动几个数，可以使得平均值为5.

思路：从最小的ai开始改动就可以了，数据不大。注意一下精度

#include "iostream"
#include "algorithm"
#include "cmath"
using  namespace std;
#define esp 1e-8
int a[105];
int main()
{
    int n,sum=0;
    cin>>n;
    for(int i=0;i>a[i];sum+=a[i];}
    sort(a,a+n);
    double ans=sum*1.0/n;
    if(ans-4.5>esp||fabs(ans-4.5)esp||fabs(ans-4.5)