import scala.io.StdIn._

object Main extends App {
  val Array(x, n) = readLine.split(" ").map(_.toInt)

  if (n > 0) {
    val p = readLine.stripMargin.split(" ").map(_.toInt).toSet

    val up = (x to 101).find(!p.contains(_)).get
    val down = (x - 1 to 1 by -1).find(!p.contains(_)).get

    val upDiff = up - x
    val downDiff = x - down

    val ans = if (downDiff <= upDiff) down else up

    println(ans)
  } else {
    println(x)
  }
}

