#!/usr/bin/env cscript
#include <stdio.h>
#include <string.h>

void rxPos(int n, char *buf)
{
	int m, address_length;
	const char *ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	char character, *address_needle, address[1 + 3]/* XFD が最大の列コードである。 */;

	for (address_length = 0, m = n;
	     m > 0; m /= strlen(ALPHABET), address_length++);

	for (m = n - 1, address_needle = address; m >= 0; m /= strlen(ALPHABET), m -= 1) {
		*address_needle++ = 'A' + m % strlen(ALPHABET);
	}

	if (address_needle > &address[strlen(address)]) {
		puts("ouch");
	}

	*++address_needle = '\0';

	switch (address_length) {
	case 2:
		character = address[0];
		address[0] = address[1];
		address[1] = character;
		break;
	case 3:
		character = address[2];
		address[2] = address[0];
		address[0] = character;
		break;
	}

	strcpy(buf, address);
}


int
main(int argc, char *argv[]) {
	char address[1 + 3];
	//rxPos(675, address);
	//printf("%s\n", address);
	rxPos(676, address);
	printf("[%s]\n", address);
	return 0;
}