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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.Set;


public class Main {

	/**
	 * @param args
	 * @throws IOException 
	 */
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());

		int[]x = new int[n];
		int[]y = new int[n];
		
		int xmin = 0;
		int ymin = 0;
		for(int i = 0; i < n; i++){
			String[] parts = br.readLine().split("\\s+");
			x[i] = Integer.parseInt(parts[0]);
			if(x[i] < 0){
				if(xmin > x[i]){
					xmin = x[i];
				}
			}
			y[i] = Integer.parseInt(parts[1]);
			if(y[i] < 0){
				if(ymin > y[i]){
					ymin = y[i];
				}				
			}
		}
		xmin = -1*xmin;
		ymin = -1*ymin;
		
		for(int i = 0; i < n; i++){
			x[i] += xmin;
			y[i] += ymin;
		}
		
		Set<String> set = new HashSet<String>();
		for(int i = 0; i < n-1; i++){
			for(int j = i+1; j < n; j++){
				for(int k = 0; k < n; k++){
					if(i == k || j == k)continue;
					if(x[i]-x[j] % 2 != 0)continue;
					if(y[i]-y[j] % 2 != 0)continue;
					int xc = Math.min(x[i], x[j]) + Math.abs(x[i]-x[j])/2; 
					int yc = Math.min(y[i], y[j]) + Math.abs(y[i]-y[j])/2;
					if(xc == x[k]&&yc == y[k]){
						set.add(toString(x[i], y[i], x[j], y[j], x[k], y[k]));
					}
				}
			}
		}
		System.out.println(set.size());
	}

	public static String toString(int i, int j, int i1, int j1, int i2, int j2) {
		return toString(i, j, i1, j1) + "+" + toString(i2, j2);
	}
	
	public static String toString(int i, int j, int i1, int j1) {
		if(i < i1){
			return toString(i, j) + ":" + toString(i1, j1);
		} else if(i == i1){
			if(j <= j1){
				return toString(i, j) + ":" + toString(i1, j1);
			} else {
				return toString(i1, j1) + ":" + toString(i, j);
			}
		}
		return toString(i1, j1) + ":" + toString(i, j);
	}
	
	public static String toString(int i, int j) {
		return i + "," + j;
	}
}
