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 D22 {
public static void main(String[] args) throws IOException {
	input.init(System.in);
	PrintWriter out = new PrintWriter(System.out);
	int n = input.nextInt();
	Pair[] data = new Pair[n];
	for(int i = 0; i<n; i++) data[i] = new Pair(input.nextInt(), input.nextInt());
	Arrays.sort(data);
	ArrayList<Integer> res = new ArrayList<Integer>();
	int last = -1111111;
	for(int i = 0; i<n; i++)
	{
		if(data[i].a > last)
		{
			res.add(data[i].b);
			last = data[i].b;
		}
	}
	out.println(res.size());
	for(int x : res) out.print(x+" ");
	out.close();
}
static class Pair implements Comparable<Pair>
{
	int a, b;
	public Pair(int aa, int bb)
	{
		a = aa; b = bb;
		if(a > b)
		{
			int temp = a; a = b; b = temp;
		}
	}
	@Override
	public int compareTo(Pair o) {
		// TODO Auto-generated method stub
		return b - o.b;
	}
}
public static class input {
	static BufferedReader reader;
	static StringTokenizer tokenizer;

	static void init(InputStream input) {
		reader = new BufferedReader(new InputStreamReader(input));
		tokenizer = new StringTokenizer("");
	}

	static String next() throws IOException {
		while (!tokenizer.hasMoreTokens())
			tokenizer = new StringTokenizer(reader.readLine());
		return tokenizer.nextToken();
	}

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

	static double nextDouble() throws IOException {
		return Double.parseDouble(next());
	}

	static long nextLong() throws IOException {
		return Long.parseLong(next());
	}
}
}

