/* Program to perform "Rotate 13" (rot13) Caesar encoding/decoding on a stream 
 * sent to standard input.
 *
 * John Nordlie 
 * April 2001
 */

#include<stdio.h>

void main() {
        unsigned char character;
        while (!feof(stdin)) {
                character = fgetc(stdin);
                if ((character < 91)&&(character > 64)) {
                        character = character + 13;
                        if (character > 90) {
                                character = character - 26;
                        }
                } else {
                        if ((character < 123) && (character > 96)) {
                                character = character + 13;
                                if (character > 122) {
                                        character = character - 26;
                                }
                        }
                }
                printf("%c", character);
        }
}