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.
p = input()

s1 = p.count('AB') - p.count('ABA') - p.count('BAB')
s2 = p.count('BA') - p.count('ABA') - p.count('BAB')

if(s1 > 0 and s2 > 0):
    print("YES")
else: print("NO")
