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.BufferedReader;
import static java.lang.Math.*;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;

public class CodeforcesSegments implements Runnable {
    BufferedReader in;
    PrintWriter out;
    StringTokenizer tok;

    public static void main(String[] args) {
        new Thread(new CodeforcesSegments()).start();
    }
    
    static class Segment implements Comparable<Segment> {

        private int l;
        private int r;

        public Segment(int l, int r) {
            this.l = min(l, r);
            this.r = max(l, r);
        }

        @Override
        public int compareTo(Segment s) {
            if(l != s.l) return l - s.l;
            return r - s.r;
        }
        
        boolean contains(int point) {
            return point >= l && point <= r;
        }
        
        public String toString() {
            return l + " " + r;
        }
    }
    

    void solve() throws IOException {
        int n = nextInt();
        ArrayList<Segment> l = new ArrayList<Segment>();
        for(int i = 0; i < n; ++i)
            l.add(new Segment(nextInt(), nextInt()));
        ArrayList<Integer> answer = new ArrayList<Integer>();
        while(!l.isEmpty()) {
            int minRight = Integer.MAX_VALUE;
            int ind = -1;
            for(int i = 0; i < l.size(); ++i) {
                if(l.get(i).r < minRight) {
                    minRight = l.get(i).r;
                    ind = i;
                }       
            }
            answer.add(minRight);
            ArrayList<Segment> temp = new ArrayList<Segment>();
            for(Segment s : l)
                if(!s.contains(minRight))
                    temp.add(s);
            l = temp;
        }
        out.println(answer.size());
        for(int coord : answer)
            out.print(coord + " ");
    }

    @Override
    public void run() {
        try {
            in = new BufferedReader(new InputStreamReader(System.in));
            // in = new BufferedReader(new FileReader(new File("input.txt")));
            out = new PrintWriter(System.out);
            //out = new PrintWriter(new File("output.txt"));
            solve();
            out.flush();
            out.close();
            in.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    String nextLine() throws IOException {
        tok = null;
        return in.readLine();
    }

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

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

    String nextToken() throws IOException {
        while (tok == null || !tok.hasMoreTokens()) {
            tok = new StringTokenizer(in.readLine());
        }
        return tok.nextToken();
    }
}
