#include <stdio.h>

int main()
{
	int X, Y;
	__int64 base[11];
	int i, L;

	for (i = 1, base[0] = 26; i < 11; i++)
	{
		base[i] = base[i - 1] * 26;
	}
	while (1)
	{
		getchar();
		scanf("%d", &X);
		getchar();
		scanf("%d", &Y);
		getchar();
		if (X == 0 && Y == 0)
		{
			break;
		}
		i = 0;
		Y -= 1;
		while (Y >= base[i])
		{
			Y -= base[i];
			i++;
		}
		i -= 1;
		while (i >= 0)
		{
			printf("%c", Y / base[i] + 'A');
			Y %= base[i];
			i--;
		}
		printf("%c%d\n", Y + 'A', X);
	}
	return 0;
}