#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <algorithm>
#include <functional>
#include <utility>
#include <bitset>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstdio>

using namespace std;

#define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)
#define snuke(c,itr) for(__typeof((c).begin()) itr=(c).begin();itr!=(c).end();itr++)

typedef long long ll;

ll x[30],y[30];
bool can[(1<<22)];

ll area(int p, int q, int r){
	return (x[q] - x[p]) * (y[r] - y[p]) - (x[r] - x[p]) * (y[q] - y[p]);
}

ll dist(int p, int q){
	return (x[q] - x[p]) * (x[q] - x[p]) + (y[q] - y[p]) * (y[q] - y[p]);
}

int main(void){
	int N,i,j,k,ans=0;
	
	cin >> N;
	REP(i,N) cin >> x[i] >> y[i];
	
	vector <int> v;
	v.push_back(0);
	v.push_back((1<<N)-1);
	
	REP(i,N) REP(j,N) if(j != i){
		int mask = 0;
		REP(k,N) if(area(i, j, k) > 0 || (area(i, j, k) == 0 && dist(i, k) > dist(j, k))) mask |= (1<<k);
		v.push_back(mask);
	}
	
	REP(i,v.size()) REP(j,i+1) REP(k,j+1) can[v[i]&v[j]&v[k]] = true;
	
	REP(i,(1<<N)) if(can[i]) ans++;
	
	cout << ans << endl;
	
	return 0;
}