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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
	    	Scanner sc = new Scanner(System.in);
	    	int a = sc.nextInt();
	    	int b = sc.nextInt();
	    	int c = sc.nextInt();
	    	int d = sc.nextInt();
	    	List<Integer> list = new ArrayList<>();
	    	list.add(a);
	    	list.add(b);
	    	list.add(c);
	    	list.add(d);
	    	Collections.sort(list);
	    	if (list.get(0) == 1 && list.get(1) == 4 && list.get(2) == 7 && list.get(3) == 9) {
	    		System.out.println("YES");
	    	} else {
	    		System.out.println("NO");
	    	}
	}
}