crystal, 112 bytes

Result

AC

Duration

2480ms

Code [DL]

a=gets('_')||""
t=a=~/T/||0
h,k=(a=~/K/||0).divmod 51
puts (a.lines[0]+'\n')*h
puts " "*k+"K"*(t-k+1)+" "*(49-t)

stdin

            T                                     
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
        K                                         

stdout

            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
            T                                     
        KKKKK                                     

stderr

strace