#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <map>
#include <set>
#include <vector>
#include <queue>
#include <iostream>
#include <cassert>
#include <bitset>
#include <ctime>

using namespace std;

typedef long long LL;
typedef double DB;
typedef pair<int, int> PII;
typedef vector<int> VI;

#define X first
#define Y second
#define pb push_back

template<class T>
inline void chkmin(T &x, T y) {
    if (y < x) x = y;
}

template<class T>
inline void chkmax(T &x, T y) {
    if (x < y) x = y;
}

#define INF 1e10
#define EPS 1e-8
#define CP const Point&

struct Point {
    int x, y;

    inline void input() {
        scanf("%d%d", &x, &y);
    }
    bool operator<(const Point &p) const {
        if (y != p.y) return y < p.y;
        return x < p.x;
    }
} O, T, p[25], pp[4];

double dis(CP p1, CP p2) {
    return hypot(p1.x - p2.x, p1.y - p2.y);
}

double vect(CP p, CP p1, CP p2) {
    return (p1.x - p.x) * (p2.y - p.y) - (p2.x - p.x) * (p1.y - p.y);
}

double scal(CP p, CP p1, CP p2) {
    return (p1.x - p.x) * (p2.x - p.x) + (p1.y - p.y) * (p2.y - p.y);
}


const int MN = 25;

int n;
int ans, cnt;
int chk[MN];
int id[MN], t;

bool right() {
    int i, j, k, t;
    
    for (i = 0; i < 4; i++) {
        j = (i + 1) % 4, k = (i + 2) % 4, t = (i + 3) % 4;
        if (fabs(dis(pp[i], pp[j]) - dis(pp[j], pp[k])) > EPS) break;
        if (fabs(vect(pp[i], pp[j], pp[k]) - vect(pp[j], pp[k], pp[t])) > EPS) break;
        if (fabs(scal(pp[i], pp[j], pp[k]) - scal(pp[j], pp[k], pp[t])) > EPS) break;
    }
    if (i == 4) return 1;
    return 0;
}

int main() {
    
//    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);
    
    int i, j, k, q, t;;
    while (scanf("%d", &n) == 1) {
        for (i = 0; i < n; i++) p[i].input();
        
        int cnt = 0;
        for (i = 0; i < n; i++) {
            for (j = i + 1; j < n; j++) {
                for (k = j + 1; k < n; k++) {
                    for (q = k + 1; q < n; q++) {
                        pp[0] = p[i];
                        pp[1] = p[j];
                        pp[2] = p[k];
                        pp[3] = p[q];
                        sort(pp, pp + 4);
                        swap(pp[2], pp[3]);
                        if (right()) cnt++;
                    }
                }
            }
        }
        printf("%d\n", cnt);
    }
    
    return 0;    
}