import scala.io.StdIn

object Main {
  def rec(idx: Int, n: Int, s: Array[Array[Char]]): Int = {
    if (idx == n * n) {
      val winCount = s.map { (ss) =>
        ss.filter(_ == 'o').size
      }

      var rank = 1
      for (i <- (0 to n).reverse) {
        if (winCount(0) == i) return rank
        if (winCount.filter(_ == i).size != 0) rank += 1
      }
    }

    val x = idx % n
    val y = idx / n

    if (s(y)(x) == '-') {
      s(y)(x) = 'o'
      s(x)(y) = 'x'
      val res1 = rec(idx + 1, n, s)
      s(y)(x) = 'x'
      s(x)(y) = 'o'
      val res2 = rec(idx + 1, n, s)
      return Math.min(res1, res2)
    } else {
      return rec(idx + 1, n, s)
    }
  }

  def main(args: Array[String]): Unit = {
    val n = StdIn.readInt
    val s = Array.fill(n)(StdIn.readLine.toArray)
    println(rec(0, n, s))
  }
}