Write a Perl program that determines whether a given column number in a 
multiple alignment (in FASTA format) is a 100% conserved. The program should
ask the user for the column number and read the multiple alignment from a
file called "dna.txt".

Submit your solution as a file called <firstname><lastname>HW10.pl to the grader
Hareesh at hc44@njit.edu and also a hardcopy in class on Oct 23rd.

For example if the input in the file dna.txt is

>human
ACCGTA
>mouse
ACCGTA
>cat
TCCTAT
>dog
ACCGAA

then the program should print "Column is conserved" if the user provides column number
2 or 3 as input and "Column is not conserved" otherwise.