#include <bits/stdc++.h>
using namespace std;

typedef long long   signed int LL;
typedef long long unsigned int LU;

#define incID(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define incII(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define decID(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define decII(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define  inc(i, n) incID(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define  dec(i, n) decID(i, 0, n)
#define dec1(i, n) decII(i, 1, n)

#define inII(v, l, r) ((l) <= (v) && (v) <= (r))
#define inID(v, l, r) ((l) <= (v) && (v) <  (r))

#define PB push_back
#define EB emplace_back
#define MP make_pair
#define FI first
#define SE second
#define PQ priority_queue

#define  ALL(v)  v.begin(),  v.end()
#define RALL(v) v.rbegin(), v.rend()
#define  FOR(it, v) for(auto it =  v.begin(); it !=  v.end(); ++it)
#define RFOR(it, v) for(auto it = v.rbegin(); it != v.rend(); ++it)

template<typename T> bool   setmin(T & a, T b) { if(b <  a) { a = b; return true; } else { return false; } }
template<typename T> bool   setmax(T & a, T b) { if(b >  a) { a = b; return true; } else { return false; } }
template<typename T> bool setmineq(T & a, T b) { if(b <= a) { a = b; return true; } else { return false; } }
template<typename T> bool setmaxeq(T & a, T b) { if(b >= a) { a = b; return true; } else { return false; } }
template<typename T> T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

// ---- ----

template<typename F, typename S> ostream & operator<<(ostream & os, const pair<F, S> & p) {
	os << "<" << p.FI << ", " << p.SE << ">";
	return os;
}

struct Frac {
	LL p, q;
	Frac() { };
	Frac(LL pp, LL qq = 1) {
		if(qq < 0) { pp *= -1; qq *= -1; }
		LL d = gcd(abs(pp), qq);
		p = pp / d; q = qq / d;
	}
	bool operator< (const Frac & obj) const { return p * obj.q <  obj.p * q; }
	bool operator> (const Frac & obj) const { return p * obj.q >  obj.p * q; }
	bool operator<=(const Frac & obj) const { return p * obj.q <= obj.p * q; }
	bool operator>=(const Frac & obj) const { return p * obj.q >= obj.p * q; }
	bool operator==(const Frac & obj) const { return p * obj.q == obj.p * q; }
	bool operator!=(const Frac & obj) const { return p * obj.q != obj.p * q; }
	Frac operator+ (const Frac & obj) const { return Frac(p * obj.q + obj.p * q, q * obj.q); }
	Frac operator- (const Frac & obj) const { return Frac(p * obj.q - obj.p * q, q * obj.q); }
	Frac operator* (const Frac & obj) const { return Frac(p * obj.p, q * obj.q); }
	Frac operator/ (const Frac & obj) const { return Frac(p * obj.q, q * obj.p); }
};
ostream & operator<<(ostream & os, const Frac & f) {
	if(f.q == 1) { os << f.p; } else { os << f.p << "/" << f.q; }
	return os;
}

// ----

typedef pair<Frac, Frac> P;
pair<int, P> cross_point(P a, P b, P c, P d) {
	// 直線 AB と直線 CD の交点を求める
	// FI: 0: 交点なし（平行） 1: 一点 2: 無限（同一直線）
	// SE: 交点の座標（FI == 1 のとき）
	assert(a != b);
	assert(c != d);
	
	Frac XAB = a.FI - b.FI;
	Frac YAB = a.SE - b.SE;
	Frac XCD = c.FI - d.FI;
	Frac YCD = c.SE - d.SE;
	
	Frac XAC = a.FI - c.FI;
	Frac YAC = a.SE - c.SE;
	if(XAB * YCD == YAB * XCD) {
		if(XAB * YAC == YAB * XAC) {
			return MP(2, MP(0, 0));
		} else {
			return MP(0, MP(0, 0));
		}
	} else {
		Frac x = Frac(XAB * YCD * c.FI - YAB * XCD * a.FI - XAB * XCD * (c.SE - a.SE)) / Frac(XAB * YCD - YAB * XCD);
		Frac y = Frac(YAB * XCD * c.SE - XAB * YCD * a.SE - YAB * YCD * (c.FI - a.FI)) / Frac(YAB * XCD - XAB * YCD);
		return MP(1, MP(x, y));
	}
}

void test() {
	P a = MP(Frac(0), Frac(0));
	P b = MP(Frac(3), Frac(2));
	P c = MP(Frac(3), Frac(0));
	P d = MP(Frac(2), Frac(3));
	cout << cross_point(a, b, c, d) << endl;
}

// ----

int n, x[200], y[200];

int g(int a, int b, int c, int d) {
	// 直線 AB と 線分 CD に共有点があれば 1, なければ 0
	P A = MP(Frac(x[a]), Frac(y[a]));
	P B = MP(Frac(x[b]), Frac(y[b]));
	P C = MP(Frac(x[c]), Frac(y[c]));
	P D = MP(Frac(x[d]), Frac(y[d]));
	
	if(A == B) { return 0; }
	auto p = cross_point(A, B, C, D);
	if(p.FI == 2) { return 1; }
	if(p.FI == 0) { return 0; }
	if(p.FI == 1) {
		if(! (C.FI <= D.FI)) { swap(C.FI, D.FI); }
		if(! (C.SE <= D.SE)) { swap(C.SE, D.SE); }
		if(inII(p.SE.FI, C.FI, D.FI) && inII(p.SE.SE, C.SE, D.SE)) { return 1; }
		return 0;
	}
}

int f(int a, int b) {
	int c = 0;
	inc(i, n) { c += g(a, b, 2 * i, 2 * i + 1); }
	return c;
}

int main() {
	// test();
	
	cin >> n;
	inc(i, n * 2) { cin >> x[i] >> y[i]; }
	
	int ans = 0;
	inc(i, n * 2) {
	inc(j, i) {
		setmax(ans, f(i, j));
	}
	}
	
	cout << ans << endl;
	
	return 0;
}