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.*;
import java.io.*;

public class Main {

	void solve (FastScanner in, PrintWriter out, Methods ms) {

		int n = in.nextInt();
		TreeSet<Integer> a = new TreeSet<>();
		for (int i=0; i<n; i++) a.add(in.nextInt());
		
		int m = in.nextInt();
		HashSet<Integer> b = new HashSet<>();
		for (int i=0; i<m; i++) b.add(in.nextInt());
		
		a.removeAll(b);
		
		for (Integer i : a) out.println(i);

	}



	public static void main(String[] args) {
		Main main = new Main();
		FastScanner in = new FastScanner(System.in);
		PrintWriter out = new PrintWriter(System.out);
		Methods ms = new Methods();
		main.solve(in, out, ms);
		in.close();
		out.close();
	}

	static class Point{

		int y, x;

		Point(int a, int b) {y = a; x = b;}
		int getY() {return y;}
		int getX() {return x;}

	}

	static class Methods {

		public void print (Object... ar) {System.out.println(Arrays.deepToString(ar));}

		public void yesno (PrintWriter out, boolean b) {out.println(b?"Yes":"No");}

		public void YESNO (PrintWriter out, boolean b) {out.println(b?"YES":"NO");}

		public int max (int... ar) {Arrays.sort(ar); return ar[ar.length-1];}

		public int min (int... ar) {Arrays.sort(ar); return ar[0];}

		public int manhat (Point p1, Point p2) {
			return Math.abs(p1.x-p2.x) + Math.abs(p1.y-p2.y);
		}

		public double euclid (Point p1, Point p2) {
			return Math.sqrt((p1.x-p2.x)*(p1.x-p2.x) + (p1.y-p2.y)*(p1.y-p2.y));
		}

		public  boolean isPrime (int n) {
			if (n==2) return true;
			if (n<2 || n%2==0) return false;
			double d = Math.sqrt(n);
			for (int i=3; i<=d; i+=2) if(n%i==0){return false;}
			return true;
		}

	}

	static class FastScanner {

		private InputStream in;
		private byte[] buffer = new byte[1024];
		private  int length = 0, p = 0;

		public FastScanner (InputStream stream) {
			in = stream;
		}

		public boolean hasNextByte () {
			if (p < length) return true;
			else {
				p = 0;
				try {length = in.read(buffer);}
				catch (Exception e) {e.printStackTrace();}
				if (length <= 0) return false;
			}
			return true;
		}

		public int readByte () {
			if (hasNextByte() == true) return buffer[p++];
			return -1;
		}

		public boolean isPrintable (int n) {return 33<=n&&n<=126;}

		public void skip () {
			while (hasNextByte() && !isPrintable(buffer[p])) p++;
		}

		public boolean hasNext () {skip(); return hasNextByte();}

		public String next () {
			if (!hasNext()) throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int t = readByte();
			while (isPrintable(t)) {
				sb.appendCodePoint(t);
				t = readByte();
			}
			return sb.toString();
		}

		public String[] nextArray (int n) {
			String[] ar = new String[n];
			for (int i=0; i<n; i++) ar[i] = next();
			return ar;
		}

		public int nextInt () {return Math.toIntExact(nextLong());}

		public int[] nextIntArray (int n) {
			int[] ar = new int[n];
			for (int i=0; i<n; i++) ar[i] = nextInt();
			return ar;
		}

		public long nextLong () {
			if (!hasNext()) throw new NoSuchElementException();
			boolean minus = false;
			int temp = readByte();
			if (temp == '-') {
				minus = true;
				temp = readByte();
			}
			if (temp<'0' || '9'<temp) throw new NumberFormatException();
			long n = 0;
			while (isPrintable(temp)) {
				if ('0'<=temp && temp<='9') {
					n *= 10;
					n += temp - '0';
				}
				else throw new NumberFormatException();
				temp = readByte();
			}
			return minus? -n : n;
		}

		public long[] nextLongArray (int n) {
			long[] ar = new long[n];
			for (int i=0; i<n; i++) ar[i] = nextLong();
			return ar;
		}

		public double nextDouble () {
			return Double.parseDouble(next());
		}

		public double[] nextDoubleArray (int n) {
			double[] ar = new double[n];
			for (int i=0; i<n; i++) ar[i] = nextDouble();
			return ar;
		}

		public void close () {
			try {in.close();}
			catch(Exception e){}
		}

	}

}