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)-1):
    if s[i]+s[i+1] == "AB":
        s = s[0:i] + "00" + s[i+3:len(s)-1]
        for j in range(len(s)-1):
            if s[j]+s[j+1] == "BA":
                ans = "YES"
print(ans)