Sum up 2
Problem
Print the sum of the given series
1/3 + 2/21 + 3/91 + 4/273 + .....
Input
Input consists of an integer N (1 <=N <= 10,000).
Output
A single line containing the sum upto Nth term (rounded upto 5 digits).
Time Limit: 1
Memory Limit: 256
Source Limit:
