enum M{M;System z;{String s=new java.util.Scanner(z.in).next();do{z.out.println(s);}while(!s.equals(s=s.replaceAll("\\$'(?=(.*))|\\$`(?<=^(.*)\\$`)","$1$2").substring(0,50)));}}
Note that non-ascii characters in the above source code will be escaped (such as \x9f).