INSTRUCTIONS

Description

Submissions

EASY $$

In Progress

Easy

In a class, the maths teacher organized a game. In the game, every student is given a badge that has a number on it$.$

The teacher instructed the students to form pairs $($each pair consists of two students$)$ so that when the minimum number from each pair is added, it results in the maximum sum possible.

Write a program that reads the badges B of the students and prints the maximum sum possible.

Input

The input will be a single line containing space$-$separated integers representing the badges B of the students.

Output

The output should be a single line containing an integer that is the maximum sum possible.

Explanation

for example