Require Import Io.System.All List ListString.All Ascii. Import ListNotations C.Notations. Fixpoint q n:=match n with 0=>ret tt|S m=>let! l:=read_line in do! match l with Some s=>log match s with[_;x;y;_;z;_;_]=>if eqb x y then [x] else [z]|_=>[] end|_=>ret tt end in q m end. Definition main:=launch(fun _=>q 32).