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()

for i in range(len(s)-1):
    if s[i:i+2] == "AB":
        s = s[:i] + s[i+2:]
        if "BA" in s:
            print("YES")
            break
        else:
            print("NO")
            break
        
    elif s[i:i+2] == "BA":
        s = s[:i] + s[i+2:]
        if "AB" in s:
            print("YES")
            break
        else:
            print("NO")
            break
            
    if i == len(s)-2:
        print("NO")