java, 332 bytes

Result

AC

Duration

1992ms

Code [DL]

import java.util.Scanner;
public class A{
public static void main(String[]a){
boolean b=false;
int d=1;
Scanner s=new Scanner(System.in);
String g;
while((g=s.nextLine())!=null){
for(int i=0;i<g.length();++i){
char c=g.charAt(i);
if(c>83)d=0;
b=c==75||b&&d>0;
System.out.print(d==0||b?"A":c+"");
d=++d%50;
}System.out.println();}}}

stdin

                                          T       
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                                  
                                K                 

stdout

                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                          A       
                                AAAAAAAAAAA       

stderr

Exception in thread "main" java.util.NoSuchElementException: No line found
	at java.base/java.util.Scanner.nextLine(Scanner.java:1651)
	at A.main(A.java:8)

strace