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()
res = []
for i in range(0,len(S),2):
    try:
        temp = list(S[i]+S[i+1])
        res.append(temp)
    except:
        break
if ['B','A'] in res and ['A','B'] in res:
    print('YES')
else:
    print('NO')
