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.
a = input()

# Find the first occurrence of "AB"
ab_index = a.find("AB")
if ab_index != -1:
    # Check if "BA" occurs after the "AB" substring
    if "BA" in a[ab_index + 2:]:
        print("YES")
        exit()

# Find the first occurrence of "BA"
ba_index = a.find("BA")
if ba_index != -1:
    # Check if "AB" occurs after the "BA" substring
    if "AB" in a[ba_index + 2:]:
        print("YES")
        exit()

print("NO")
