You are given n segments on the coordinate axis Ox and the number k. The point is satisfied if it belongs to at least k segments. Find the smallest (by the number of segments) set of segments on the coordinate axis Ox which contains all satisfied points and no others.

Input

The first line contains two integers n and k (1 ≤ k ≤ n ≤ 106) — the number of segments and the value of k.

The next n lines contain two integers li, ri ( - 109 ≤ li ≤ ri ≤ 109) each — the endpoints of the i-th segment. The segments can degenerate and intersect each other. The segments are given in arbitrary order.

Output

First line contains integer m — the smallest number of segments.

Next m lines contain two integers aj, bj (aj ≤ bj) — the ends of j-th segment in the answer. The segments should be listed in the order from left to right.

Examples

Input

3 2
0 5
-3 2
3 8


Output

2
0 2
3 5


Input

3 2
0 5
-3 3
3 8


Output

1
0 5
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.Arrays;
import java.io.BufferedWriter;
import java.util.InputMismatchException;
import java.io.BufferedReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Writer;
import java.util.StringTokenizer;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Andrey Rechitsky (arechitsky@gmail.com)
 */
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();
        int k = in.nextInt();
        long d = 1000000000l;
        long[] events = new long[2*n];
        for (int i = 0; i < n; i++) {
            long l = d+ in.nextInt();
            long r = d+in.nextInt();
            events[i]=((l<<32l)|i);
            events[i+n]=((r<<32l)|(1l<<31l)|i);
        }
        Arrays.sort(events);
        int depth = 0;
        long [] l = new long[n];
        long [] r = new long[n];
        int s = 0;
        for (long val:events){
            if ((val&(1l<<31l))==0){
                depth++;
                if (depth==k)l[s]=val>>32l;
            }
            else{
                if (depth==k)r[s++]=val>>32l;
                depth--;
            }
        }
        out.printLine(s);
        for (int i = 0; i < s; i++) {
            out.print(l[i]-d);
            out.print(' ');
            out.printLine(r[i]-d);
        }
    }

}

class FastScanner {

    private BufferedReader reader;
    private StringTokenizer st;

    public FastScanner(InputStream stream) {
        this.reader = new BufferedReader(new InputStreamReader(stream));
        this.st = new StringTokenizer("");
    }

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

    public String next() {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(readLine());
        }
        return st.nextToken();
    }

    private String readLine() {
        String line = tryReadLine();
        if (line == null) throw new InputMismatchException();
        return line;
    }

    private String tryReadLine() {
        try {
            return reader.readLine();
        } catch (IOException e) {
            throw new InputMismatchException();
        }
    }

}

class FastPrinter {
    private final PrintWriter writer;

    public FastPrinter(OutputStream outputStream) {
        writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
    }

    public void close() {
        writer.close();
    }

    public void printLine(long i) {
        writer.println(i);
    }

    public void print(long i) {
        writer.print(i);
    }

    public void print(char c) {
        writer.print(c);
    }

}
