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.
# Wadea #
 
s = input()
a = 0
b = 0
if "AB" in s:
    a += 1
    r = s.index("AB")
    
if "BA" in s:
    b += 1
    q = s.index("BA")
if a > 0 and b > 0:
    if r+1 == q:
        print("NO")
    elif r+1 != q:
        print("YES")
else:
    print("NO")