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.
string = input()

ans = []
count = 0
i = 1 
sett =set()

while i < len(string):
    if (string[i-1] == "A" and string[i] == "B") or (string[i-1] == "B" and string[i] == "A"):
        sett.add(string[i-1]+string[i])
        i += 2  # Increment i by 2 when the condition is true to skip the next character
    else:
        i += 1  
if len(sett) >=2:
    print("YES")
else:
    print("NO")