open String;;let r s =let rec q=make 1 (char_of_int 34) and a s=let l=length s-1 in if l>=0then (a (sub s 1 l); print_char s.[0]) in a s;print_string(q^s^q)in r"r ni)q^s^q(gnirts_tnirp;s a ni )]0[.s rahc_tnirp ;)l 1 s bus( a( neht0=>l fi ni 1-s htgnel=l tel=s a dna )43 tni_fo_rahc( 1 ekam=q cer tel= s r tel;;gnirtS nepo"