#include <map>
#include <set>
#include <list>
#include <stack>
#include <queue>
#include <deque>
#include <cmath>
#include <ctime>
#include <cstdio>
#include <vector>
#include <bitset>
#include <sstream>
#include <cstdlib>
#include <complex>
#include <climits>
#include <cstring>
#include <iostream>
#include <algorithm>

#define REP(i,N) for (int i = 0;i < (N);i++)
#define REP_1(i,N) for (int i = 1;i < (N);i++)
#define REP_2(i,be,en) for (int i = (be);i < (en);i++)
#define DWN(i,N) for (int i = (N);i >= 0;i--)
#define DWN_1(i,N) for (int i = (N);i >= 1;i--)
#define DWN_2(i,en,be) for (int i = (en);i >= (be);i--)
#define FR(N) freopen((N),"r",stdin)
#define FW(N) freopen((N),"w",stdout)
#define SO(N) scanf("%d",&(N))
#define STO(N,M) scanf("%d %d",&(N),&(M))
#define STH(N,M,K) scanf("%d %d %d",&(N),&(M),&(K))
#define PS(N) printf("%d",(int)(N));
#define MAXN 2010
#define GETS(ch) fgets((ch),MAXN,stdin)
#define INF 0x3f3f3f3f
#define MOD 1000000007
using namespace std;

typedef long long LL;
typedef LL ll;
typedef map<int,LL> MINT;
typedef map<char,int> MCH;
typedef map<string,int> MSTR;

typedef vector<int> VINT;
typedef set<LL> SINT;
typedef pair<int,int> PINT;

LL read(){
    LL ret=0,f=1;
    char x=getchar();
    while(!(x>=‘0‘ && x<=‘9‘)){if(x==‘-‘)f=-1;x=getchar();}
    while(x>=‘0‘ && x<=‘9‘) ret=ret*10+x-‘0‘, x=getchar();
    return ret*f;
}

class point {
public:
    int x,y;
}node[30];
point List[5];

int cross(point p0,point p1,point p2) //计算叉积  p0p1 X p0p2
{
    return (p1.x-p0.x)*(p2.y-p0.y)-(p1.y-p0.y)*(p2.x-p0.x);
}
double dis(point p1,point p2)  //计算 p1p2的 距离
{
    return sqrt((double)(p2.x-p1.x)*(p2.x-p1.x)+(p2.y-p1.y)*(p2.y-p1.y));
}
bool cmp(point p1,point p2) //极角排序函数 ， 角度相同则距离小的在前面
{
    int tmp=cross(List[0],p1,p2);
    if(tmp>0) return true;
    else if(tmp==0&&dis(List[0],p1)<dis(List[0],p2)) return true;
    else return false;
}

int cross2(point p0,point p1,point p2) //计算点积  p0p1 · p1p2
{
    return (p1.x-p0.x)*(p2.x-p1.x)+(p1.y-p0.y)*(p2.y-p1.y);
}


int ans = 0;
int work(vector<int> V) {
    int len = V.size();
    for (int i = 1;i < len;i++) {
        if (node[V[i]].x < node[V[0]].x) {
            swap(V[i],V[0]);
        }
        else if (node[V[i]].x == node[V[0]].x) {
            if (node[V[i]].y < node[V[0]].y) {
                swap(V[i],V[0]);
            }
        }
    }
    for (int i = 0;i < len;i++) {
        List[i] = node[V[i]];
    }
    sort(List,List + len,cmp);
    for (int i = 0;i < len - 1;i++) {
        if (dis(List[i],List[i + 1]) - dis(List[i + 1],List[(i + 2) % len]) > 1e-6) return 0;
        if (cross2(List[(i + len - 1) % len],List[i],List[i + 1]) != 0) return 0;
    }

    return 1;
}
int N;

void dfs(int u,int pos,vector<int> V,int num) {
    if (pos == num) {
        ans += work(V);
        return;
    }
    if (u >= N) return;
    V.push_back(u);
    dfs(u + 1,pos + 1,V,num);
    V.pop_back();
    dfs(u + 1,pos,V,num);
}

int main() {
    while (cin >> N) {
        for (int i = 0;i < N;i++) {
            cin >> node[i].x >> node[i].y;
        }
        vector<int> V;
        V.clear();
        ans = 0;
        dfs(0,0,V,4); // 只能形成4边形
        cout << ans << endl;
    }
}