import scala.collection._
object Main extends App {
    val Array(n, m) = scala.io.StdIn.readLine().split("\\s").map(_.toInt)
    var cnt_array = mutable.Seq[Int]()

    for (i <- 1 to 31){
        cnt_array :+= 0
    }

    for (i<-1 to n){
    val tmp_array = scala.io.StdIn.readLine().split("\\s").map(_.toInt)
    val k = tmp_array.take(1)
    val as = tmp_array.drop(1)
      for (j <- 0 until k(0)){
        cnt_array(as(j)) = cnt_array(as(j)) + 1
      }
    }

    var result = 0
    for (i<- cnt_array){
      if (i == n){
        result += 1
      }
    }

    println(result)
}