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.
s = input()

def fun(s):
    count = 0
    i = 0
    while i<len(s)-1:
        if s[i:i+2]=="AB" or s[i:i+2]=="BA":
            count+=1
            if count>=2:
                return "YES"
            i+=1
        i+=1
    return "NO"

print(fun(s))
