Description

There are several students in a class. Given the age (integer) of each student, calculate the average age of all students in the class, rounded to two decimal places.

Input Format

The first line contains an integer n (1 ≤ n ≤ 100), representing the number of students. The following n lines each contain one integer, representing the age of each student, with values between 15 and 25.

Output Format

Output a single line containing a floating-point number, representing the average age, rounded to two decimal places.

Sample

2
18
17

17.50