[백준/Java] 5597번 과제 안 내신 분..?

-Code

import java.util.Scanner;


public class _5597 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int[] arr = new int[31];
		for (int i = 0; i < 28; i++) {
			int n = sc.nextInt();
			arr[n] = 1;
		}
		
		for (int j = 1; j < 31; j++) {
			if (arr[j] == 0) {
				System.out.println(j);
			}
		}
	}

}