#include <stdio.h>

char rot13(char c);

int
main(int argc, char *argv[])
{
	char c;

	if (argc < 2) {
		printf("%c\n", 7); // bell
		return 1;
	}

	for (int i = 1; i < argc; i++) {
		for (int j = 0; argv[i][j] != '\0'; j++) {
			c = rot13(argv[i][j]);
			printf("%c", c);
		}
	}

	printf("\n");
	
	return 0;
}

char
rot13(char c)
{
	/* assume lowercase first */
	if ((c > 122) || (c < 97)) goto notlower;

	c -= 97;
	c = (c + 13) % 26;
	c += 97;

	return c;

notlower:
	if ((c > 90) || (c < 65)) return c;

	c -= 65;
	c = (c + 13) % 26;
	c += 65;

	return c;
}