#!/usr/bin/env cscript
#include <stdio.h>
#include <string.h>
#define ALPHABET "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

int
main(int argc, char *argv[]) {
	int value, needle;
	char column_index[3 + 1];

	for (needle = 0, value = 26; value > 0; value /= strlen(ALPHABET) + 1, needle++) {
		column_index[needle] = ALPHABET[(value - 1) % (strlen(ALPHABET) + 1)];
	}

	printf("[%s]\n", column_index);
}