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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php

function input(string $func = null) {
    if ($func === null) {
        return trim(fgets(STDIN));
    } else {
        return $func(trim(fgets(STDIN)));
    }
}

function input_array(string $func = null) {
    if ($func === null) {
        return explode(' ', trim(fgets(STDIN)));
    } else {
        return array_map(function($v) use ($func) {
            return $func($v);
        }, explode(' ', trim(fgets(STDIN))));
    }
}

$ns = input_array('intval');
sort($ns);

if ($ns === [1, 4, 7, 9]) {
    echo "YES\n";
} else {
    echo "NO\n";
}