Vinnimobil#1857
Vinnimobil is a state-of-the-art, high-tech, and environmentally ultra-clean vehicle powered by linden honey. Linden honey, as is well known, is an extremely energy-efficient fuel: its consumption rate is barrel per mile. The Vinnimobil's tank can hold exactly barrel of honey. Transporting honey in other containers is prohibited, as there is a risk that the driver might simply eat it. However, it is permitted to pour honey from the tank onto the roadside, so that it can later be collected and put back into the tank (most interestingly, without loss).
Winnie wants to reach Piglet, who lives at a distance of miles, using the Vinnimobil and spending, of course, the minimum amount of honey. How many barrels will Winnie use?
The input file contains a real number (0 \leq x \leq 5).
Output the amount of honey in barrels required for Winnie, with three decimal places of precision.
Example 1