use strict;
use warnings;

my @seq; # DNA sequence strings

for my $count (1 .. 4) {
    print "Please enter DNA sequence $count:";
    push @seq, scalar <STDIN>;
}

chomp @seq; # Remove line endings on all entries

printf "%2d: %s\n", length $_, $_ for  sort {length $a <=> length $b} @seq;