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(s):
    if "AB" in s:
        index_AB = s.index("AB")
        if "BA" in s[index_AB + 2:]:
            return "YES"
    
    if "BA" in s:
        index_BA = s.index("BA")
        if "AB" in s[index_BA + 2:]:
            return "YES"
    
    return "NO"

print(check(input()))
