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


my $string = "ASDTDAAFRASEQSAAAFDG";

my %acids;

for(my $i = 0; $i < length($string)-1; $i++){
	my $amino = substr($string, $i, 2);
	
	if(exists $acids{$amino}){
		$acids{$amino}++;
	}else{
		$acids{$amino} = 1;
	}
		
	#print "$amino\n";

}

print "These are the occurrence of all amino acid pairs including overlaps as separate counts\n";
foreach my $amino(keys %acids){
	print "$amino\t$acids{$amino}\n";
}