import java.util.Scanner

object Main {
  def solve(sc: => Scanner): Unit = {
    val N = sc.nextInt
    if (N != 0) {
      var z = false
      for (_ <- 0 until N) {
        val X = sc.nextInt
        if (X == 0) (z = true)
      }
      println(if (z) ("NA") else (N + 1))
      solve(sc)
    }
  }


  def main(args: Array[String]): Unit = {
    val sc: Scanner = new Scanner(System.in)

    solve(sc)
  }
}