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 C (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>

int main(){
	int n[4];
	scanf("%d %d %d %d", &n[0], &n[1], &n[2], &n[3]);
	for(int i = 0; i < 4; i++){
		for(int j = i+1; j < 4; j++){
			if(n[i] > n[j]){
				int tmp = n[i];
				n[i] = n[j];
				n[j] = tmp;
			}
		}
	}
	
	//printf("%d %d %d %d", n[0], n[1], n[2], n[3]);
	if(n[0] == 1 && n[1] == 4 && n[2] == 7 && n[3] == 9) puts("YES");
	else puts("NO");
			
	return 0;
}