Problem:
Score : 100 points

Problem Statement

You are given four digits N_1, N_2, N_3 and N_4. Determine if these can be arranged into the sequence of digits "1974".

Constraints

0 \leq N_1, N_2, N_3, N_4 \leq 9

N_1, N_2, N_3 and N_4 are integers.

Input

Input is given from Standard Input in the following format:

N_1 N_2 N_3 N_4

Output

If N_1, N_2, N_3 and N_4 can be arranged into the sequence of digits "1974", print YES; if they cannot, print NO.

Sample Input 1

1 7 9 4

Sample Output 1

YES

We can get 1974 by swapping N_2 and N_3.

Sample Input 2

1 9 7 4

Sample Output 2

YES

We already have 1974 before doing anything.

Sample Input 3

1 2 9 1

Sample Output 3

NO

Sample Input 4

4 9 0 8

Sample Output 4

NO

Solution in Scala (2.11.7) (judge verdict: Accepted)

object Main {
  import java.util.Scanner

  def readStrings(n: Int)(implicit sc: Scanner): Array[String] = Array.fill(n) { sc.next() }
  def readInts(n: Int)(implicit sc: Scanner): Array[Int] = Array.fill(n) { sc.nextInt() }
  def readLongs(n: Int)(implicit sc: Scanner): Array[Long] = Array.fill(n) { sc.nextLong() }
  def readLineStrings(implicit sc: Scanner): Array[String] = sc.nextLine().split(' ')
  def readLineInts(implicit sc: Scanner): Array[Int] = readLineStrings.map(_.toInt)
  def readLineLongs(implicit sc: Scanner): Array[Long] = readLineStrings.map(_.toLong)

  def main(args: Array[String]): Unit = solve(new Scanner(System.in))

  def solve(implicit sc: Scanner): Unit = {
    val N = readLineInts
    if(Seq(1, 7, 9, 4).map(n => N.count(_ == n) == 1).forall(identity)) {
      println("YES")
    } else {
      println("NO")
    }
  }
}