fun main() {
    val N = readLine()!!.toInt()

    var left=1
    var right=N
    var MIN=1
    var MAX=N-1

    repeat(10) {
        val mid = (left+right)/2
        println("? $mid")

        val x = readLine()!!.toInt()

        if ((x-MIN)<(MAX-x)){
            right=mid
            MAX=x
        }
        else{
            left=mid
            MIN=x
        }
    }

    println("Yes $left $right")
}