Problem F. 6. Diagonal
Input file name: standard input
Output file name: standard output
Time limit: 1 s
Memory limit: 1024 MB
Output file name: standard output
Time limit: 1 s
Memory limit: 1024 MB
In a square grid of size n, all numbers from 1 to n^2 are filled in spiral order, starting from the center.
Calculate the sum of the numbers that lie on both diagonals.
Input
An odd integer n (1 \le n \le 3 \cdot 10^{5}).
Output
Print the answer.
Example
| standard input | standard output |
|---|---|
| 3 | 25 |
| 7 | 261 |