Problem:
Score : 100 points

Problem Statement

In AtCoder City, there are three stations numbered 1, 2, and 3.

Each of these stations is operated by one of the two railway companies, A and B. A string S of length 3 represents which company operates each station. If S_i is A, Company A operates Station i; if S_i is B, Company B operates Station i.

To improve the transportation condition, for each pair of a station operated by Company A and one operated by Company B, there will be a bus service connecting them.

Determine if there is a pair of stations that will be connected by a bus service.

Constraints

Each character of S is A or B.

|S| = 3

Input

Input is given from Standard Input in the following format:

S

Output

If there is a pair of stations that will be connected by a bus service, print Yes; otherwise, print No.

Sample Input 1

ABA

Sample Output 1

Yes

Company A operates Station 1 and 3, while Company B operates Station 2.

There will be a bus service between Station 1 and 2, and between Station 2 and 3, so print Yes.

Sample Input 2

BBA

Sample Output 2

Yes

Company B operates Station 1 and 2, while Company A operates Station 3.

There will be a bus service between Station 1 and 3, and between Station 2 and 3, so print Yes.

Sample Input 3

BBB

Sample Output 3

No

Company B operates all the stations. Thus, there will be no bus service, so print No.

Solution in PyPy3 (2.4.0) (judge verdict: Accepted)

# coding:utf-8

import sys
import math
import time
#import numpy as np
import collections
from collections import deque
import queue
import copy
import bisect


def dfs(s, prev, pre):
  val[s] += Ope[s] + prev
  for i in G[s]:
    if(i == pre):
      continue
    dfs(i, val[s], s)

def bfs(sx, sy, n):
  que = deque([[sy,sx]])
  while que:
    y,x = que.popleft()
    for i,j in D:
      if(x+i<0 or y+j<0 or x+i>W-1 or y+j>H-1):
        continue
      dist = G[y+j][x+i]
      if(G[y+j][x+i] != "X"):
        if(type(G[y+j][x+i]) is str):
          G[y+j][x+i] = G[y][x]+1
          que.append([y+j,x+i])
        elif(dist>G[y][x]+1):
          G[y+j][x+i] = G[y][x]+1
          que.append([y+j,x+i])
        

#X = str(input()).split()
#a = [int(x) for x in input().split()]
#sys.setrecursionlimit(10**7)
#N, Q = map(int, input().split())
#G = [list(input()) for i in range(H)]

S = str(input())
ans = "Yes"

if(S=="AAA" or S=="BBB"):
  ans = "No"
  

print(ans)