#!/usr/bin/perl -w
   use strict;
   open DATA , "<GSE_out" or die "Can't open the file $!";
   my @output = <DATA>;
   my $count_A = 0 ;
  close DATA ;
foreach my $line (@output)
 {
    my $length = length ($line);
   
     if (substr($line, 0,$length) eq 'A')
     {
         $count_A++;
     }
  print $count_A++;

##</code><code>##

>2
AAAAAAAAACAAAAGAACGAAGAAGT
>3
AAAAAAAAACAACCGAAAAATAGAAAC
>4
AAAAAAAAACAAGAAGGACTAGACC
>7
AAAAAAAAACAAGGACTGGTTTATCAG
>8
AAAAAAAAACAAGTTTCTCTGTGACT
>12
AAAAAAAAACACAGACGTAGAATTGT
>14
AAAAAAAAACACGACCGTTCGCTTTGA
>15
AAAAAAAAACACGACTGTTCGCTTT
>16
AAAAAAAAACACTATGAGCCAGAAC