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()

def fun(s,ff,ss):
    i = 0
    FF,SS = False,False
    while i<len(s)-1:
        if s[i:i+2]==ff:
            FF = True
            break
        i+=1
    i+=2
    while i<len(s)-1:
        if s[i:i+2]==ss:
            SS = True
        i+=1

    return FF&SS
if fun(s,"AB","BA") or fun(s,"BA","AB") :
    print("YES")
else:
    print( "NO")
