10
-2 1
2 -2
-1 -2
0 0
2 -1
0 -2
2 2
0 2
-1 -1
1 -2
 40
-8 24
2 -1
1 -18
72 -70
5 -4
-308 436
-19 40
36 -35
-178 265
-1 2
-7 30
-1 0
3 -2
200 -285
17 -16
-35 74
0 -4
-86 106
-1 4
-7 6
0 1
-5 4
-2 3
6 -5
-4 5
181 -262
76 -118
0 0
-7 18
-58 104
-5 6
-6 12
-3 4
1 0
11 -10
-86 130
-3 6
153 -236
-183 270
-33 64
 5
0 -1
0 -2
0 -3
0 -4
0 -5
 10
0 1
-1 -1
1 1
-1 0
1 -1
-2 -1
-2 2
-2 0
0 -2
0 -1
 20
-1 18
-2 5
-5 4
2 -33
9 -18
0 0
11 -22
2 0
-1 2
-4 41
1 6
1 -2
6 -12
0 1
-3 6
3 -6
3 -8
-1 4
2 -5
1 0
 10
2 1
-1 0
-2 -1
-1 1
0 2
2 -2
0 0
-2 -2
0 -2
-2 1
 20
-3 -3
0 4
-3 1
1 1
-1 2
-4 4
3 -1
-3 0
0 2
4 0
2 3
2 4
4 -3
-4 3
-1 1
1 3
-2 4
1 -2
1 -1
3 0
 3
0 0
0 -1
0 1
 10
2 1
-1 1
0 0
-3 1
-2 -3
-1 -2
-1 -1
1 2
3 -2
0 -2
 3
3 3
1 2
1 1
 4
0 0
1 0
2 0
3 0
 9
1 1
1 0
0 1
0 0
-1 0
-1 1
-1 -1
1 -1
0 -1
 7
1 1
-1 -1
1 0
0 1
-1 0
0 -1
0 0

4
 57
 4
 5
 21
 4
 10
 1
 1
 0
 2
 8
 3

import java.io.*;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.math.*;

public class B
{
        String line;
        StringTokenizer inputParser;
        BufferedReader is;
        FileInputStream fstream;
        DataInputStream in;
        String FInput="";
        
        void openInput(String file)
        {

                if(file==null)is = new BufferedReader(new InputStreamReader(System.in));//stdin
                else
                {
                        try{
                
                                
                        fstream = new FileInputStream(file);
                        in = new DataInputStream(fstream);
                        is = new BufferedReader(new InputStreamReader(in));
                        }catch(Exception e)
                        {
                                System.err.println(e);
                        }
                }

        }
        
        void readNextLine()
    	{
    		try {
    			line = is.readLine();
    			inputParser = new StringTokenizer(line, " ");
    			//System.err.println("Input: " + line);
    		} catch (IOException e) {
    			System.err.println("Unexpected IO ERROR: " + e);
    		}	
    		catch (NullPointerException e)
    		{
    			line=null;
    			
    		}
    		
    	}
        
        long NextLong()
        {
                String n = inputParser.nextToken();
                
                long val = Long.parseLong(n);
                
                 return val;
        }
        
        int NextInt()
        {
                String n = inputParser.nextToken();
                int val = Integer.parseInt(n);
                
                //System.out.println("I read this number: " + val);
                return val;
        }
        
        String NextString()
        {
                String n = inputParser.nextToken();
                return n;
        }
        
        void closeInput()
        {
                try {
                        is.close();
                } catch (IOException e) {
                        System.err.println("Unexpected IO ERROR: " + e);
                }
                        
        }
        
        
        public static void main(String [] argv)
        {
                String filePath=null;
                if(argv.length>0)filePath=argv[0];
                new B(filePath);
        }
        
        public void readFInput()
    	{
    		for(;;)
    		{
    			try
    			{
    				readNextLine();
    				FInput+=line+" ";
    			}
    			catch(Exception e)
    			{
    				break;
    			}
    		}
    		inputParser = new StringTokenizer(FInput, " ");
    	}
        
       
        public B(String inputFile)
        {
        	openInput(inputFile);
    		readNextLine();
    		
    		int N=NextInt();
    		int ret=0;
    		boolean [] [] p = new boolean [3000][3000];
    		for(int i=0; i<N; i++)
    		{
    			readNextLine();
    			p[NextInt()+1500][NextInt()+1500]=true;
    			
    		}
    		
    		for(int i=0; i<3000; i++)
    			for(int j=0; j<3000; j++)
    			{
    				if(!p[i][j])continue;
    				for(int x=i; x<3000; x++)
    					for(int y=j; y<3000; y++)
    					{
    						if(!p[x][y])continue;
    						if(x==i&&j==y)continue;
    						int a=i+2*(x-i);
    						if(a>=3000)continue;
    						int b=j+2*(y-j);
    						if(b>=3000)continue;
    						if(p[a][b])ret++;
    					}
    			}
    		System.out.print(ret);
            closeInput();		
    	}


        


}