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 Kotlin (1.0.0) (judge verdict: Accepted)

fun main(args: Array<String>) {
    val array0 = readLine()!!.split(" ").map { s -> s.toInt() }

    val list1974 = mutableListOf(1, 9, 7, 4)
    for (n in array0) {
        when (n) {
            1 -> list1974.remove(1)
            9 -> list1974.remove(9)
            7 -> list1974.remove(7)
            4 -> list1974.remove(4)
        }
    }
    if (list1974.size==0){
        print("YES")
    }else{
        print("NO")

    }

}