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.
def helper(s):
    l1,l2=[],[]
    for i in range(len(s)-1):
        if s[i]=='A' and s[i+1]=='B':l1.append(i)
        elif s[i]=='B' and s[i+1]=='A':l2.append(i)
    if len(l1)>=2 or len(l2)>=2:return "YES"
    if len(l1)==1 and len(l2)==1:
        if l1[0]-1!=l2[0] and l2[0]+1!=l1[0]+2:return "YES"
        else:return "NO"
    return "NO"
    
import sys
input=sys.stdin.readline
from collections import defaultdict
s=input().rstrip()
print(helper(s))