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()
i = 1
ab =False
ba =False
while i<len(s):
    if s[i] =="A" and s[i-1]=="B":
        ba=True
        i+=1
    elif s[i] == "B" and s[i-1] == "A":
        ab =True
        i+=1
    i+=1
    if ab and ba:
        print("YES")
        break
else :
    print("NO")