Problems
Find the sum 2
Find the sum 2
For the given value of n find the sum
\dfrac{1}{sin\:1} + \dfrac{1}{sin\:1 + sin\:2} + ... + \dfrac{1}{sin\:1 + sin\:2 + ... + sin\:n}
Input data
One integer n\:(n \le 1000).
Output data
Print the value of the sum with 6 decimal digits.
Examples
Input example #1
3
Output example #1
2.288145