my %hash=(); 
%hash=(
##keys between "" because of dots
"M01.001" =>["M01.001"]'
"M01.001.111" =>["M01.001.111"]'
"M01.001.111.111" =>["M01.001.111.111"]'
"M01.002" =>["M01.002"]'
"M01.002.003" =>["M01.002.003"]'
)

for my $k(sort keys %hash){
	  my $temp = reverse($k);
	  $temp =~ s/^\d{3}\.?//;
	  my $t= reverse ($temp);
	     if (exists $hash{$t}){
	     $hash{$k}[1] += 1;
     	     } 
}