You are given n segments on the Ox-axis. You can drive a nail in any integer point on the Ox-axis line nail so, that all segments containing this point, are considered nailed down. If the nail passes through endpoint of some segment, this segment is considered to be nailed too. What is the smallest number of nails needed to nail all the segments down?

Input

The first line of the input contains single integer number n (1 ≤ n ≤ 1000) — amount of segments. Following n lines contain descriptions of the segments. Each description is a pair of integer numbers — endpoints coordinates. All the coordinates don't exceed 10000 by absolute value. Segments can degenarate to points.

Output

The first line should contain one integer number — the smallest number of nails needed to nail all the segments down. The second line should contain coordinates of driven nails separated by space in any order. If the answer is not unique, output any.

Examples

Input

2
0 2
2 5


Output

1
2 

Input

5
0 3
4 2
4 8
8 10
7 7


Output

3
7 10 3
import java.io.*;
import java.util.*;

public class Main implements Runnable {
	class Segment implements Comparable<Segment> {
		int x;
		int y;

		public Segment(int x, int y) {
			if (x > y) {
				int tmp = x;
				x = y;
				y = tmp;
			}
			this.x = x;
			this.y = y;
		}

		@Override
		public int compareTo(Segment other) {
			if (y != other.y) {
				return y - other.y;
			} else {
				return x - other.x;
			}
		}
	}

	public void solution() throws IOException {
		List<Integer> res = new ArrayList<Integer>();
		List<Segment> seg = new ArrayList<Segment>();
		int n = in.nextInt();
		for (int i = 0; i < n; ++i) {
			seg.add(new Segment(in.nextInt(), in.nextInt()));
		}
		Collections.sort(seg);
		boolean[] used = new boolean[n];
		for (int i = 0; i < n; ++i) {
			if (!used[i]) {
				res.add(seg.get(i).y);
				for (int j = i + 1; j < n; ++j) {
					if (seg.get(j).x <= seg.get(i).y && seg.get(i).y <= seg.get(j).y) {
						used[j] = true;
					}
				}
			}
		}
		out.println(res.size());
		for (int i = 0; i < res.size(); ++i) {
			if (i != 0) {
				out.print(' ');
			}
			out.print(res.get(i));
		}
		out.println();
	}

	public void run() {
		try {
			solution();
			in.reader.close();
			out.close();
		} catch (Throwable e) {
			e.printStackTrace();
			System.exit(1);
		}
	}

	private class Scanner {
		private BufferedReader reader;
		private StringTokenizer tokenizer;

		public Scanner(Reader reader) {
			this.reader = new BufferedReader(reader);
			this.tokenizer = new StringTokenizer("");
		}

		public boolean hasNext() throws IOException {
			while (!tokenizer.hasMoreTokens()) {
				String next = reader.readLine();
				if (next == null) {
					return false;
				}
				tokenizer = new StringTokenizer(next);
			}
			return true;
		}

		public String next() throws IOException {
			hasNext();
			return tokenizer.nextToken();
		}

		public int nextInt() throws IOException {
			return Integer.parseInt(next());
		}

		public String nextLine() throws IOException {
			tokenizer = new StringTokenizer("");
			return reader.readLine();
		}
	}

	public static void main(String[] args) throws IOException {
		new Thread(null, new Main(), "", 1 << 28).start();
	}
	PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
	Scanner in = new Scanner(new InputStreamReader(System.in));
}
