import java.util.Scanner

object Problem239 {
  def main(args: Array[String]) {
    val sc = new Scanner(System.in)
    val N = sc.nextInt
    val said = List.fill(N, N)(sc.next)

    val transposeSaid = said.transpose.zip(Stream from 1)
    val rentyonppoiMember = transposeSaid.filter(_._1.forall(say => say == "nyanpass" || say == "-"))
    val tokutei = rentyonppoiMember.length == 1

    if (tokutei) {
      println(rentyonppoiMember.head._2)
    } else {
      println(-1)
    }
  }
}