Calculate the sum of interior angles of an $ N $-sided polygon.

Input

The only line of input contains the integer $ N $.

Output

Output the sum of interior angles of the polygon, in degrees.

Subtasks

Subtask 1 (70%): $ 3 \le N \le 1000 $
Subtask 2 (30%): $ 3 \le N \le 2 \times 10^7 $