#include <stdio.h>

int print(char c, int times) {
	if (times <= 0) {
		return 0;
	}
	else {
		printf("%c", c);
		print(c, --times);
	}
}

int main(void)
{
	int num, hole;
	scanf("%d%d", &num, &hole);

	if (num >= hole) {
		print('A', hole);
		print('C', num - hole);
	}
	if (num < hole) {
		print('A', 2 * num - hole);
		print('B', hole - num);
	}

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