# Duelists

"Among the open valley...". 1883. "Among the open valley..." - classic Shishkin. The artist often fond of sending poetic motifs, which he saw in nature. So, following the once-popular song, AF Merzlyakov in this picture he was trying to express the greatness of the mighty lonely oak, towering among latitude fields.

Among the open valley, On a smooth adjustment, Bloom, grow tall oak In the powerful beauty. High spreading oak, They have all one in the eyes; One, one, poor thing How to Recruit on the clock! Does the red sun rises - Anyone under the canopy to take? Hit the weather - Who will defend? Oh, boring lonely And a tree grow! Ah, bitter, bitter dashing No dear life to lead!

Among the open valley Peter Ivanovich, and Ilya Vasilevitch decided to investigate the relationship in a duel. But none of them wanted to die. Therefore, they agreed that each of them comes to an oak (meeting place) at random time between 5 and 6 o'clock in the morning and, after waiting for an opponent n minutes, is removed. In case of arrival of the latter in this duel will take place n minutes. Calculate the probability that the duel will end duel.

## Input

Each line is a separate test and contains an integer n (0 < n ≤ 60). Output

For each test on a separate line to derive the probability that the duel will end duel. Result output up to 6 decimal places.