+/(#@~.@;);._2<;._1 LF,1!:1<'day06'  NB. 6612
+/(#@((e.#[)/)@:>);._2<;._1 LF,1!:1<'day06'  NB. 3268
+/(*/@e.#@~.@#;);._2<;._1 LF,1!:1<'day06'  NB. FireFly
+/,([:*/a.e."1>);._2<;._1 LF,1!:1<'day06'  NB. shorter