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.
def check_substrings(s):
    # Look for the first occurrence of "AB" or "BA"
    index_ab = s.find("AB")
    index_ba = s.find("BA")

    # Check if both substrings were found
    if index_ab != -1 and index_ba != -1:
        # Check if the substrings are not overlapping
        if abs(index_ab - index_ba) > 1:
            return "YES"

    # Look for the first occurrence of the other substring
    index_ab = s.find("AB", index_ba + 2)
    index_ba = s.find("BA", index_ab + 2)

    # Check if both substrings were found
    if index_ab != -1 and index_ba != -1:
        # Check if the substrings are not overlapping
        if abs(index_ab - index_ba) > 1:
            return "YES"

    return "NO"

# Read the input string
s = input()

# Check if the string contains the required substrings
result = check_substrings(s)

# Print the result
print(result)
