Maxim Vitalievich was invited to a birthday party. He chose, in his opinion, an excellent gift — a cake in the form of a regular convex $$$n$$$-gon.
The holiday is in full swing, Maxim Vitalievich has already congratulated the birthday man and received a responsible task from him — it is necessary to cut the cake into pieces, not necessarily of equal size. The main condition is that the pieces are triangles.
Maxim Vitalyevich asked himself the question, what is the minimum number of cuts needed to divide the cake into triangles. It is allowed to cut the cake only along diagonals (straight lines passing through a pair of $$$n$$$-gon vertices).
The single line contains an integer $$$n$$$ — the number of vertices in the polygon.
$$$$$$ 4 \le n \le 100 $$$$$$
Print a single number — the minimum number of cuts required to divide the cake into triangular pieces.
5
2
8
4
