#include <iostream>
#include <fstream>
#include <stdlib.h>
#include <math.h>

using namespace std;

struct dot{
    double x, y;
};

double dotDistance(double x1, double y1, double x2, double y2);

int main()
{
    int N, result = 0;
    freopen("triang.in", "rt", stdin);
    freopen("triang.out", "wt", stdout);
    cin >> N;

    dot v[N];

    for(int i = 0; i < N; i++)
        cin >> v[i].x >> v[i].y;

    for(int i = 0; i < N - 2; i++)
        for(int j = i + 1; j < N - 1; j++)
            for(int l = j + 1; l < N && (abs(dotDistance(v[i].x,v[i].y,v[j].x,v[j].y) - dotDistance(v[j].x,v[j].y,v[l].x,v[l].y)) < 0.0001 &&
                (abs(dotDistance(v[j].x,v[j].y,v[l].x,v[l].y) - dotDistance(v[i].x,v[i].y,v[l].x,v[l].y)) < 0.0001)); l++)
                result++;

    cout << result;


    return 0;
}

double dotDistance(double x1, double y1, double x2, double y2)
{
    double len = sqrt((y2 - y1)*(y2 - y1) + (x2 - x1)*(x2 - x1));
    return len;
}