SOLUTIONS Programming Contest - Sum of Interior Angles

Given an integer N not less than 3, find the sum of the interior angles of a regular polygon with N sides.

Print the answer in degrees, but do not print units.

Constraints

• 3 \leq N \leq 100

Input

Input is given from Standard Input in the following format:

N

Output

Print an integer representing the sum of the interior angles of a regular polygon with N sides.

Examples

Input

3

Output

180

Input

100

Output

17640

inputFormat

Input

Input is given from Standard Input in the following format:

N

outputFormat

Output

Print an integer representing the sum of the interior angles of a regular polygon with N sides.

Examples

Input

3

Output

180

Input

100

Output

17640

样例

3

180