import java.util.Scanner


object Main extends App {
  val scanner = new Scanner(System.in)
  val n = scanner.nextInt()
  val arr = new Array[Int](n)
  var c = 0
  var c2 = 0

  for (i <- 0 until n) {
    arr.update(i, scanner.nextInt())
    if (arr(i) % 2 == 0)
      c += 1
    else
      c2 += 1
  }

  val mn = Integer.min(c, c2)
  c2 -= mn

  println(mn + c2 / 3)

}