You are given string *s*. Your task is to determine if the given string *s* contains two non-overlapping substrings "AB" and "BA" (the substrings can go in any order).
The only line of input contains a string *s* of length between 1 and 10<sup class="upper-index">5</sup> consisting of uppercase Latin letters.
c = input()
found_ab = False
found_ba = False

# Find the first occurrence of "AB"
ab_index = c.find("AB")
if ab_index != -1:
    # Find the first occurrence of "BA" after the "AB"
    ba_index = c.find("BA", ab_index + 2)
    if ba_index != -1:
        found_ab = True
        found_ba = True

# Find the first occurrence of "BA"
ba_index = c.find("BA")
if ba_index != -1:
    # Find the first occurrence of "AB" after the "BA"
    ab_index = c.find("AB", ba_index + 2)
    if ab_index != -1:
        found_ab = True
        found_ba = True

if found_ab and found_ba:
    print("YES")
else:
    print("NO")
