A. Sum of Odds
time limit per test
15 seconds
memory limit per test
1024 megabytes
input
standard input
output
standard output

As a child, Techno heard a story about Gauss who was able to quickly calculate the sum of numbers from 1 to 100. Gauss' technique was to add 1 to 100, 2 to 99, 3 to 98, and so on until 50 to 51. Thus, the sum would be 101 times the number of pairs: 50.

Mini technoblade not impressed by Gauss idea, written in the white board above

Everyone is always impressed by this story, except Techno. He decided to do something more impressive and find the sum of the first $$$n$$$ odd numbers: 1 + 3 + 5 ... + $$$2n-1$$$.

Input

The input consists of a single integer $$$n$$$, $$$1 \leq n \leq 10^7$$$.

Output

Print on a single line the integer representing the sum of the first $$$n$$$ odd numbers: $$$1 + 3 + 5 ... + (2n-1)$$$.

Note that this number does NOT fit in a 32-bit integer. In C/C++, use "long long int" for the answer and for $$$n$$$, or use Python.

Examples
Input
1
Output
1
Input
2
Output
4
Input
3
Output
9
Input
10000000
Output
100000000000000
Note

For $$$n = 1$$$, the sum is just 1.

For $$$n = 2$$$, the sum is $$$1 + 3 = 4$$$.

For $$$n = 3$$$, the sum is $$$1 + 3 + 5 = 9$$$.

For $$$n = 4$$$, the sum is $$$1 + 3 + 5 + 7 = 16$$$. And so on.