The cost of a bottle of water (including the cost of the empty bottle) is 1 dollar 20 cents. The cost of the empty bottle is 20 cents.

How many bottles of water is it possible to drink for n dollars, if you can recycle bottles for cash and buy new bottles of water for this cach.

Input

Positive integer n (1 ≤ n ≤ 1000).

Output

Number of bottles of water that you can drink for n dollars.