import scala.io.StdIn.readLine
 
object Main {
  def search(a:Array[Int],len:Int,value:Int) = {
    def scan(l:Int,r:Int):Boolean = {
      val mid = (l+r)/2
      if(a(mid) == value) true
      else if(l>=r) false
      else if(a(mid)<value) scan(mid+1,r)
      else scan(l,mid-1)
    }
    scan(0,len)
  }
 
  def main(args:Array[String]) = {
    readLine
    val s = readLine.split(" ").map(_.toInt)
    readLine
    val t = readLine.split(" ").map(_.toInt)
    val len = s.length-1
    println(t.count(i=> search(s,len,i) ))
  }
}