import Foundation

/*
// 1
let N = Int(readLine()!)!

// 1 2
let split = readLine()!.componentsSeparatedByString(" ")
let N = Int(split[0])!
let S = Int(split[1])!

// 1 2 3 4 5
let array = readLine()!.componentsSeparatedByString(" ").map { Int($0)! }

func pow(_ number: Int, multiplier: Int) -> Int {
  var answer = 1
  for _ in 0 ..< multiplier {
    answer *= number 
  }
  return answer
}


*/
let N = readLine()!
let A = "AAA"
let B = "BBB"
if N == A || N == B{
  print("No")
} else {
print("Yes")
}