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 Ruby (2.3.3) (judge verdict: Accepted)

# AtCoder 市には 3 つの駅があり、1,2,3 の番号がつけられています。
# これらの駅は、それぞれ鉄道会社A, Bのいずれかが管理しています。
# 管理状況は長さ 3 の文字列 S で表され、
# 駅 i は Si が A のとき鉄道会社 A が、
# B のとき鉄道会社 B が管理しています。
# 鉄道会社 A が管理している駅と、鉄道会社 B が管理している駅の間には、
# 交通の便のためにバスを運行することになりました。
# 実際にバスが運行することになる駅の組み合わせが存在するかどうかを判定してください。

s = gets

if s.include?("A") && s.include?("B")
    puts "Yes"
else
    puts "No"
end