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.
s = input()

try:
    if "BA" in s[s.index("AB")+2:]:
        print("YES")
    else:
        print("NO")
except ValueError:
    try:
        if "AB" in s[s.index("BA")+2:]:
            print("YES")
        else:
            print("NO")
    except ValueError:
        print("NO")

"""
//////////////////////////////////////////
//                                      //
//      Implemented by brownfox2k6      //
//                                      //
//////////////////////////////////////////
"""