use v5.10;
@hat=split/ /,<DATA>;
while(@hat){
  ($hat=>$littlecat)=splice@hat,0,2;
  $littlecat{$hat}=$littlecat>$littlecat{$hat}?$littlecat:$littlecat{$hat};
}
say+join" ",map"$_ $littlecat{$_}",sort{$littlecat{$b}<=>$littlecat{$a}}keys%littlecat;
__DATA__
one.fish 1 blue.fish -20 one.fish 0 blue.fish -1 blue.fish 0 fish-red.fish ,and one.fish 2