func main()
	var n: int :: cui@inputInt()
	var d: int :: cui@inputInt()
	
	var s: []char
	if(d <= n)
		do s :: "A".repeat(d) ~ "C".repeat(n - d)
	else
		do s :: "A".repeat(2 * n - d) ~ "B".repeat(d - n)
	end if
	do cui@print("\{s}\n")
end func