Write a Perl program that prints the three longest DNA sequences from a
set given in FASTA format. 

Submit your solution as a file called <firstname><lastname>HW11.pl to the grader
Hareesh at hc44@njit.edu and also a hardcopy in class on Oct 27th.

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

>A
ACCGTA
>B
ACCGTAACCTTG
>C
TCCTATAA
>D
ACC
>E
ACACAGTTTGCGCGCGCGGGG
>F
GCTTTAAAAAGGCAA
>G
ATGTA
>H
GCGCCCCCCA

then the program should print 

ACACAGTTTGCGCGCGCGGGG
GCTTTAAAAAGGCAA
ACCGTAACCTTG

Your program should work for any input file and not just this example.