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: Runtime Error)

import java.util.*;
 
public class Main {
	public static void main(String[] args){
    	Scanner sc = new Scanner(System.in);
		String K = "keyence";
		String S = sc.next();
        boolean fl = false;
        int l = S.length();
      	
      	for(int i=6;0<=i;i--){
        	if(S.substring(0,i)== K.substring(0,i)){
        		if(S.substring(l-(6-i))==K.substring(i)){
                	System.out.println("YES");
                    fl = true;
                  	break;
                }
            }
        
        }
      	if(!fl){
          System.out.println("NO");
        }
     } 
}