4

object magic {
  val f1:(Int,Int) =>Int =_+_
  val f2:(Int,Int) =>Int=_+_
  def test(fn:(Int,Int)=>Int,x:Int,y:Int):Int={
    fn(x,y)
  }
  def main(args:Array[String]):Unit={
    println(test(f1,10,  20))
    println(test(f2,10,  20))
  }

}