Migrated from Lutece 612 Seven Dices

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Description

Mr.Sun has seven dices. A dice has six faces, each showing a different number from $1$ to $6$, and having the equal probability to face up after thrown.

One day, he is so bored that he begins to repeatedly throw the seven dices. He throws all the dices together, and adds up the numbers shown on each dice. And now, he wants to know the probability that he gains the total points he desires each time he throws.

Input

There are several test cases, end by EOF. For each case, there is one integers: $C$ ($C \leq 100$), the total points Mr.Sun desires.

Output

For each case, output one real number indicating the probability, round to four decimal places.

Samples

10
20

0.0003
0.0545

Resources

6th BUPT Programming Contest Final