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.
a = input()
count = 0
for i in range(len(a)-1):
    if (a[i] == 'A' and a[i+1] == 'B'):
        for j in range(i+2, len(a)-1):
            if (a[j] == 'B' and a[j+1] == 'A'):
                count += 1
                break
        break

if count >= 2:
    print('YES')
else:
    print('NO')
