my $freqocurrence={};
sub freq_oc{
    foreach my $key (keys %$observation){
        $total10 += $observation->{$key};
    }


foreach my $key (keys %$observation){
    $freqocurrence->{$key} = $observation->{$key}/$total10;
    print "Frequency of ocurrence:     Aminoacid $key-> $freqocurrence->{$key}\n";
    
    }

}

print Dumper $freqocurrence;