#include <stdio.h>

int print(char c,int times) {
	printf("%c",c);
	times != 1 && print(c,--times);
	return 0;
}

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

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