// Libraries
fun string(): String = readLine()!!
fun int(): Int = readLine()!!.toInt()
fun long(): Long = readLine()!!.toLong()
fun stringList(): List<String> = readLine()!!.split(" ")
fun intList(): List<Int> = readLine()!!.split(" ").map(String::toInt)
fun longList(): List<Long> = readLine()!!.split(" ").map(String::toLong)

// 最大公約数(ユーグリットの互除法)
tailrec fun gcd(a: Int, b: Int): Int = when {
    a < b -> gcd(b, a)
    b == 0 -> a
    else -> gcd(b, a % b)
}

fun main(args: Array<String>) {
    val s = string().toCharArray()

    if(s[0] == s[1] && s[1] == s[2]) {
        println("No")
    }else{
        println("Yes")
    }
}