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().upper()
i = 0
ab, ba,aba = 0,0,0
while i<len(s)-1:
    if s[i:i+3] in ["BAB","ABA"]:
        ab+=1
        ba+=1
        aba+=1
        i+=2
    elif s[i]=="A" and s[i+1]=="B":
        ab +=1
        i+=1
    elif s[i]=="B" and s[i+1]=="A":
        ba+=1
        i+=1
    i+=1
    if ab>0 and ba>0 and (not aba==ba==ab==1):
        print("YES")
        break
else:print("NO")