import java.io.*;
import java.util.*;
import java.math.*;
import java.text.*;


public class diplomatic {


    public static void main(String[] args) throws Exception {
	BufferedReader f = new BufferedReader(new FileReader("diplomatic.in"));
	StringTokenizer st;

	String line;
	
	while ((line = f.readLine()) != null) 
	{
	
		st = new StringTokenizer(line);
		long num = Long.parseLong(st.nextToken());
	
		//long x[]= new long[num];
		//long y[]= new long[num];
		
		long x1, y1, x2, y2, x0 ,y0;
	
		System.out.print(num+" ");
		x1 = Long.parseLong(st.nextToken());
		y1 = Long.parseLong(st.nextToken());
	
	x0 = x1;
	y0 = y1;
	
		for (int i = 1; i < num; i++)
		{		
	  		x2 = Long.parseLong(st.nextToken());
	  		y2 = Long.parseLong(st.nextToken());	
	  		System.out.print(((x2+x1)/2l)+" "+((y2+y1)/2l)+" ");
				x1 = x2;
				y1 = y2;
				
		}
		
		System.out.print((x1+x0)/2l+" "+(y1+y0)/2l+"\n");

	}


    }
}