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.
a=input()
x=[]
y=[]
for i in range(len(a)):
    if a[i:i+2]=="AB":
        x.append(i)
    elif a[i:i+2]=="BA":
        y.append(i)
for i in range(len(x)):
    for j in range(len(y)):
        if x[i]-y[j]>1 or x[i]-y[j]<-1:
            print("YES")
            exit()
print("NO")


