Write a program that takes a positive whole number, n, and if n is even, performs the computation suggested by these examples, and prints the value of the computation. If n is odd, it prints nonsensical input.

input n	computation	output
4	(2/2)+(2+4)/4	2.5
6	(2/2)+(2+4)/4+(2+4+6)/6	4.5
8	(2/2)+(2+4)/4+(2+4+6)/6+(2+4+6+8)/8	7
3		nonsensical input