Problems

# Buy the water

# Buy the water

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 data

Positive integer n (1 ≤ n ≤ 1000).

## Output data

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

## Examples

Input example #1

2

Output example #1

1