erlang, 128 bytes

Result

AC

Duration

1494ms

Code [DL]

main(Z)->f(1,Z).
f(X,S)->Y=case C=io:get_chars(S,1)of"T"->1;"K"->X-50;eof->halt();_->X+1end rem 51,f(Y,if X<1->"@";0<1->C end).

stdin

                                                 T
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                  K               

stdout

                                                 T
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                                 @
                                  K@@@@@@@@@@@@@@@

stderr

strace