my @compounds=("C3H8O2",
           "C6H10O5",
           "C36H62O31",
           "C5H16N2",
           "C10H11N5O6P",
           "C9H11N3O7P",
           "C3H9N2O2");
print join("\n",
         map { $_->[0] }
         sort { $a->[1] <=> $b->[1] }
         map { [ $_, (/C(\d+)/)[0] }
         grep { $_ =~ /P/} 
         @compounds
),"\n";