B. Blinds
time limit per test
2 seconds
memory limit per test
512 megabytes
input
standard input
output
standard output

Your friend Mitrofan's window has blinds made of $$$n$$$ plates ($$$1 \leqslant n \leqslant 12$$$). Each plate can be opened or closed. Initially, all plates are open. There are three buttons on the blinds: red, blue and black.

  • When you press the red button, the mechanism finds the highest open plate, closes it and opens all plates above it.
  • When you press the blue button, the mechanism finds the lowest open plate, closes it and opens all the plates below it.
  • If all slats are already closed, the blinds will break when either of these two buttons is pressed.
  • When you press the black button, the mechanism opens all closed plates.

It is not known why Mitrofan did not please you, but now you most of all want to know what is the minimal number of button presses needed to break the blinds.

Input

The single line contains the number $$$n$$$, the number of plates in the blinds ($$$1\leqslant n \leqslant 12$$$).

Output

Print a single integer, the minimal number of button presses needed to break the blinds.

Examples
Input
2
Output
3
Input
3
Output
5