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.
line = input()
A = []
B = []
for i in range (len(line)-1):
    current = line[i:i+2]
    if current == "AB":
        A.append(i)
    elif current == "BA":
        B.append(i)
printed = True
for ind in A:
    if ind-1 not in B and ind+1 not in B and len(B)!=0:
        print("YES")
        printed = False
    else:
        continue
if printed:
    print("NO")