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.
import sys, io, os
import math
import bisect
import heapq
import string
from collections import defaultdict,Counter,deque
input = sys.stdin.readline
 
def I():
    return input()
 
def II():
    return int(input())
 
def MII():
    return map(int, input().split())
 
def LI():
    return list(input().split())
 
def LII():
    return list(map(int, input().split()))
 
def GMI():
    return map(lambda x: int(x) - 1, input().split())
 
def LGMI():
    return list(map(lambda x: int(x) - 1, input().split()))
 
def WRITE(out):
  return print('\n'.join(map(str, out)))
 
def WS(out):
  return print(' '.join(map(str, out)))
 
def WNS(out):
  return print(''.join(map(str, out)))

def WSNOPRINT(out):
  return ''.join(map(str, out))

'''
'''
def solve():
    s = [x for x in I().strip()]
    seen = set()
    while s:
        if len(s) >= 2:
            seen.add(''.join(s[-2:]))
            s.pop()
            s.pop()
        else:
            s.pop()
    
    print('YES' if 'AB' in seen and 'BA' in seen else 'NO')

solve()