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.
word = input()  # Read the input string
length = len(word)
found_ab = False
found_ba = False

for i in range(length - 1):
    if not found_ab and word[i:i+2] == "AB":  # Check for "AB" substring
        found_ab = True
        for j in range(i+2, length - 1):  # Start from the next index after "AB"
            if word[j:j+2] == "BA":  # Check for "BA" substring
                found_ba = True
                break
    if not found_ba and word[i:i+2] == "BA":  # Check for "BA" substring
        found_ba = True
        for j in range(i+2, length - 1):  # Start from the next index after "BA"
            if word[j:j+2] == "AB":  # Check for "AB" substring
                found_ab = True
                break
    if found_ab and found_ba:
        break

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