#!usr/bin/perl -w
use strict;

my $string = "ASDTDAAFRASEQSAAAFDG";
my $counter = 0;

for(my $i = 0; $i < length($string)-1; $i++){
	my $amino = substr($string, $i, 2);
	
	$counter++ if($amino eq "AA");
	
	#print "$amino\n";

}

print "number of AA matches = $counter\n";