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
cd = 0
length = len(word)

for i in range(length - 1):  # Loop only up to the second last index
    if word[i:i+2] == "AB":  # Check for "AB" substring
        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
                cd = 2  # Set cd to 2 to indicate both substrings found
                break
    if word[i:i+2] == "BA" and cd != 2:  # Check for "BA" substring only if cd is not already 2
        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
                cd = 2  # Set cd to 2 to indicate both substrings found
                break

if cd == 2:
    print("YES")
else:
    print("NO")