Average Age

Problem Description

A class has some number of students. Given each student's age (an integer), compute the average age of all students in the class, kept to two decimal places.

Input Format

The first line contains an integer $\,n\,$ ($1 \le n \le 100$), the number of students. The following $\,n\,$ lines each contain one integer, the age of a student, ranging from $15$ to $25$.

Output Format

Output one line containing a floating-point number: the required average age, kept to two decimal places.

Sample Input

2
18
17

Sample Output

17.50