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.
"""
    author:  Adham0      
    created: 03.08.2023 17:06:38
    ### Adham was here ###
 
     █████  ██████  ██   ██  █████  ███    ███
    ██   ██ ██   ██ ██   ██ ██   ██ ████  ████
    ███████ ██   ██ ███████ ███████ ██ ████ ██
    ██   ██ ██   ██ ██   ██ ██   ██ ██  ██  ██ 
    ██   ██ ██████  ██   ██ ██   ██ ██      ██
"""

s = input()

if "BA" not in s or "AB" not in s:
    print("NO")
    exit()

pos = s.index("BA")
if "AB" in s[pos + 2:]:
    print("YES")
    exit()

pos = s.index("AB")
if "BA" in s[pos + 2:]:
    print("YES")
    exit()

print("NO")