Problem: The main building of the nation is developing complex patterns as each day progresses.
The task is to find the number of three sided closed figures on the nth day.

(Input – n

Output – number of triangles)

SAMPLE INPUT
2

SAMPLE OUTPUT
5

Solution (in PYTHON):

Solution:
days=int(input())
if days==1:
	print(1)
else:
	print((days*(days+2)*(days*2+1))/8)