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()
i=0;n=len(s)-1
cx=[];cy=[]
while(i<n):
    if s[i]=='A' and s[i+1]=='B':
        cx.append(i)
    elif s[i]=='B' and s[i+1]=='A':
        cy.append(i)
    i+=1
if(v(cx[0],cy[-1]) or v(cy[0], cx[-1])):
    print("YES")
else:
    print("NO")
def v(x, y):
    return True if min(x,y)+1!=max(x,y)