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()

condition1 = False
condition2 = False
i = 0

while i < len(s):
    if s[i] == "A":
        if i < len(s)-1 and s[i+1] == "B":
            condition1 = True
            i += 2
        else:
            i += 1

    elif s[i] == "B":
        if i < len(s)-1 and s[i+1] == "A":
            condition2 = True
            i += 2
        else:
            i += 1

    else:
        i += 1

if condition1 and condition2:
    print("YES")
else:
    print("NO")


