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.*;

//java.is.awesome

public class R22qDSegments {

	public static void main(String[] args) {
		InputReader in = new InputReader(System.in);
		PrintWriter w = new PrintWriter(System.out);

		int n = in.nextInt();
		Pair p[] = new Pair[n];
		for(int i = 0; i < n; i++)
			p[i] = new Pair(in.nextInt() , in.nextInt());
		
		Arrays.sort(p);
		
		int L = -100000, R = -100000;
		int ans = 0;
		ArrayList<Integer> wow = new ArrayList<Integer>();
		
		for(int i = 0 ; i < n; i++){
			int L2 = Math.max(L, p[i].x);
			int R2 = Math.min(R , p[i].y);
			if(L2 <= R2){
				L = L2;
				R = R2;
			}
			else{
				ans++;
				wow.add(R);
				L = p[i].x;
				R = p[i].y;
			}
		}
		
		wow.add(L);
		wow.remove(0);
		w.println(ans);
		for(int x : wow)
			w.print(x + " ");
		w.println();
		w.close();
	}
	
	static class Pair implements Comparable<Pair>{
		int x,y;
		Pair(int x,int y){	this.x = Math.min(x, y); this.y = Math.max(x, y); }
		public int compareTo(Pair o){
			if(x != o.x)
				return Integer.compare(x, o.x);
			return Integer.compare(y, o.y);
		}
		public String toString(){
			return x + " " + y;
		}
	}

	static class InputReader {

		private InputStream stream;
		private byte[] buf = new byte[8192];
		private int curChar, snumChars;
		private SpaceCharFilter filter;

		public InputReader(InputStream stream) {
			this.stream = stream;
		}

		public int snext() {
			if (snumChars == -1)
				throw new InputMismatchException();
			if (curChar >= snumChars) {
				curChar = 0;
				try {
					snumChars = stream.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (snumChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public int nextInt() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public long nextLong() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = snext();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = snext();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

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

		public String readString() {
			int c = snext();
			while (isSpaceChar(c))
				c = snext();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = snext();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public boolean isSpaceChar(int c) {
			if (filter != null)
				return filter.isSpaceChar(c);
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		public interface SpaceCharFilter {
			public boolean isSpaceChar(int ch);
		}
	}
}