use strict;

my %data;
my $headers = <DATA>;
while ( my $line = <DATA>) {
  chomp $line;
  my ($os,$release,$like) = split(/,/,$line);
  ++$data{$os}{$release}{ uc $like };
}

for my $os (sort keys %data) {
  for my $release (sort keys %{ $data{$os} } ) {
    my $yes = $data{$os}{$release}{'YES'} || '0';
    my $no = $data{$os}{$release}{'NO'} || '0';
    print "$os, $release, $yes, $no\n"; 
  }
}

__DATA__
OS,RELESASE,LIKE
Ubuntu,Warty,No
Ubuntu,Hoary,No
Ubuntu,Breezy,Yes
Ubuntu,Breazy,Yes
Fedora,Yarrow,Yes
Fedora,Stentz,No
Fedora,Yarrow,Yes
Fedora,Yarrow,Yes
Windows,XP PRO,Yes
Windows,XP PRO,Yes
Windows,XP Home,No
Windows,XP PRO,Yes