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()
ans = "NO"
for i in range(len(s)):
    try:
        if s[i] == "A" and s[i+1] == "B":
            if "BA" in s[i+3:]:
                ans = "YES"
                break
        elif s[i] == "B" and s[i+1] == "A":
            if "AB" in s[i+3:]:
                ans = "YES"
                break
    except:
        ans = "NO"
print(ans)