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.util.List;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.ArrayList;
import java.util.Comparator;
import java.io.BufferedReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Random;
import java.io.Reader;
import java.io.Writer;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Niyaz Nigmatullin
 */
public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		FastScanner in = new FastScanner(inputStream);
		FastPrinter out = new FastPrinter(outputStream);
		TaskD solver = new TaskD();
		solver.solve(1, in, out);
		out.close();
	}
}

class TaskD {
    public void solve(int testNumber, FastScanner in, FastPrinter out) {
        int n = in.nextInt();
        Segment[] a = new Segment[n];
        for (int i = 0; i < n; i++) {
            a[i] = new Segment(in.nextInt(), in.nextInt());
        }
        Arrays.sort(a, new Comparator<Segment>() {
            public int compare(Segment o1, Segment o2) {
                return o1.b - o2.b;
            }
        });
        int last = Integer.MIN_VALUE;
        List<Integer> answer = new ArrayList<Integer>();
        for (Segment e : a) {
            if (last < e.a) {
                answer.add(e.b);
                last = e.b;
            }
        }
        out.println(answer.size());
        out.printArray(ArrayUtils.toPrimitiveArrayInteger(answer));
    }

    static class Segment {
        int a;
        int b;

        Segment(int a, int b) {
            if (a > b) {
                int t = a;
                a = b;
                b = t;
            }
            this.a = a;
            this.b = b;
        }
    }
}

class FastScanner extends BufferedReader {

    boolean isEOF;

    public FastScanner(InputStream is) {
        super(new InputStreamReader(is));
    }

    public int read() {
        try {
            int ret = super.read();
            if (isEOF && ret < 0) {
                throw new InputMismatchException();
            }
            isEOF = ret == -1;
            return ret;
        } catch (IOException e) {
            throw new InputMismatchException();
        }
    }

    static boolean isWhiteSpace(int c) {
        return c >= -1 && c <= 32;
    }

    public int nextInt() {
        int c = read();
        while (isWhiteSpace(c)) {
            c = read();
        }
        int sgn = 1;
        if (c == '-') {
            sgn = -1;
            c = read();
        }
        int ret = 0;
        while (!isWhiteSpace(c)) {
            if (c < '0' || c > '9') {
                throw new NumberFormatException("digit expected " + (char) c
                        + " found");
            }
            ret = ret * 10 + c - '0';
            c = read();
        }
        return ret * sgn;
    }

    }

class FastPrinter extends PrintWriter {

    public FastPrinter(OutputStream out) {
        super(out);
    }

    public FastPrinter(Writer out) {
        super(out);
    }

    public void printArray(int[] a) {
        for (int i = 0; i < a.length; i++) {
            if (i > 0) {
                print(' ');
            }
            print(a[i]);
        }
        println();
    }


}

class ArrayUtils {

    static public int[] toPrimitiveArrayInteger(List<Integer> list) {
        int[] ret = new int[list.size()];
        for (int i = 0; i < ret.length; i++) {
            ret[i] = list.get(i);
        }
        return ret;
    }


    }

