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 cnt;
  int n[4];
  int f[10] = {0,};
  int i;

  cnt = scanf("%d %d %d %d", &n[0], &n[1], &n[2], &n[3]);

  for (i=0; i<4; i++){
    f[n[i]] = 1;
  }

  if (f[1] && f[9] && f[7] && f[4]) {
    printf ("YES");
  } else {
    printf ("NO");
  }
  
  return 0;
}