Problem Statement

You are a teacher and want to calculate the average grade of your students for a particular subject. Write a program that takes the grades of five students as input and calculates their average grade.

Constraints

• All input grades are float numbers between 0 and 100
• The output average is a float number

Input

Input is in the following format:

grade1
grade2
grade3
grade4
grade5

Output

average

Samples

Sample 1

Sample 2

Sample 3