let p,s=print_endline,String.sub let rec f i j a b c=let(!)k=p(s k i(16-i)^(s k 0 i))in !b;!c;!a;p"";f((i+1)mod 16)(j-j/j)b c a;;Scanf.scanf"%s@ %s@ %s@_"(f 1 47)
Note that non-ascii characters in the above source code will be escaped (such as \x9f).