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.InputStreamReader;

import java.util.HashMap;
import java.util.HashSet;

public class Triplets{
        private static double computeSlope(int x1, int y1, int x2, int y2){
                return (double)(y2-y1)/(double)(x2-x1);
        }
        public static void main(String[] argv) throws Exception{
                BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
                int n=Integer.parseInt(br.readLine().trim());
                int[] x=new int[n], y=new int[n];
                String[] words;
                for(int i=0; i<n; i++){
                    words=br.readLine().trim().split(" ");
                    x[i]=Integer.parseInt(words[0]); y[i]=Integer.parseInt(words[1]);
                }
                HashMap<Double, HashSet<Integer>> slopeMap=new HashMap<Double, HashSet<Integer>>();
                double slope;
                for(int i=0; i<n; i++){
                        for(int j=i+1; j<n; j++){
                                slope=computeSlope(x[i], y[i], x[j], y[j]);
                                if(!slopeMap.containsKey(slope)){
                                        slopeMap.put(slope, new HashSet<Integer>());
                                }
                                slopeMap.get(slope).add(i);
                                slopeMap.get(slope).add(j);
                        }
                }
                int c;
                long ans=0;
                for(Double m: slopeMap.keySet()){
                        c=slopeMap.get(m).size();
                        if(c>=3){
                                ans+=(long)(c-2)*(long)(c-1)/2;
                        }  
                }
                System.out.println(ans);
        }
}
