Description

There are several students in a class. Given each student's age (an integer), 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, indicating the age of each student, with values ranging from 15 to 25.

Output Format

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

2
18
17

17.50