print "enter sequence and signal end with enter followed by ctrl d\n";
$sequence = <STDIN>;
chomp $sequence;
print "sequence inserted : $sequence\n";
@trips = unpack("a3" x (length($sequence)-2), $sequence);
@trips = join(" ", @trips);
 use List::Util 'shuffle';
@shuffled = shuffle(@trips);
print "@shuffled\n";