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.
string = input()

foundAB = False
foundBA = False

for i in range(len(string) - 1):
    if not foundAB and string[i:i+2] == 'AB':
        foundAB = True
        continue
    
    if not foundBA and string[i:i+2] == 'BA':
        foundBA = True
        continue
    
    if foundAB and foundBA:
        print("YES")
        break

if not foundAB or not foundBA:
    print("NO")
