You are given the following pyramid:

1

2 3

4 5 6

7 8 9 10

..........

Your task is to find the sum of all prime numbers in the nth line.

Example:

- primesum(1) = 0

- primtsum(2) = 5

- [input] integer n

1 ≤ n ≤ 1000

- [output] integer