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];
	int one=0,seven=0,nine=0,four=0;
	int i;
	
	scanf("%d %d %d %d",&N[0],&N[1],&N[2],&N[3]);
	
	for(i=0;i<4;i++){
		if(N[i]==1)	one++;
		if(N[i]==9)	nine++;
		if(N[i]==7)	seven++;
		if(N[i]==4)	four++;
	}
	
	if(one==1 && nine==1 && seven==1 && four==1)	printf("YES");
	else	printf("NO");
	
	return 0;
}