my @seq_01 = 
  qw (B C D F G H J K L M N P Q R S T V X Y Z);
my @seq_02 = 
  qw (BB CC DD FF GG HH JJ KK LL MM NN PP QQ RR SS TT VV XX YY ZZ);
my @seq_03 = 
  qw (BBB CCC DDD FFF GGG HHH JJJ KKK LLL MMM NNN PPP QQQ RRR SSS TTT VVV XXX YYY ZZZ);
my @merged_seq = (@seq_01, @seq_02, @seq_03);