%%
[a-z]	{ char ch = yytext[0];
          ch += 3;
          if (ch > 'z') ch -= ('z'+1-'a');
          printf ("%c", ch);
        }
          
[A-Z]	{ char ch = yytext[0];
          ch += 3;
          if (ch > 'Z') ch -= ('Z'+1-'A');
          printf ("%c", ch);
        }
%%