Problem:
Set Difference

Find the difference of two sets $A = \{a_0, a_1, ..., a_{n-1}\}$ and $B = \{b_0, b_1, ..., b_{m-1}\}$, $A - B$.

Input

The input is given in the following format.

$n$
$a_0 \; a_1 \; ... \; a_{n-1}$
$m$
$b_0 \; b_1 \; ... \; b_{m-1}$

Elements in $A$ and $B$ are given in ascending order. There are no duplicate elements in each set.

Output

Print elements in the difference in ascending order. Print an element in a line.

Constraints

$1 \leq n, m \leq 200,000$

$0 \leq a_0 < a_1 < ... < a_{n-1} \leq 10^9$

$0 \leq b_0 < b_1 < ... < b_{m-1} \leq 10^9$

Sample Input 1

5
1 2 3 5 8
2
2 5

Sample Output 1

1
3
8

Solution in JAVA (judge verdict: Accepted)

import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		TreeSet<Integer> set = new TreeSet<>();
		int n = sc.nextInt();
		for (int i = 0; i < n; i++) {
		    set.add(sc.nextInt());
		}
		int m = sc.nextInt();
		for (int i = 0; i < m; i++) {
		    int x = sc.nextInt();
		    if (set.contains(x)) {
		        set.remove(x);
		    }
		}
		StringBuilder sb = new StringBuilder();
		for (int x : set) {
		    sb.append(x).append("\n");
		}
		System.out.print(sb);
	}
}