Description

Given the length, width, and height of a rectangular prism, calculate its surface area.

Input Format

One line containing three integers $a$, $b$, $c$ ($1 \le a, b, c \le 10^7$), representing the length, width, and height of the rectangular prism respectively.

Output Format

One line containing one integer, representing the surface area of the rectangular prism.

Sample

1 2 3

22