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#include <functional>
#include <algorithm>
#include <iostream>
#include <numeric>
#include <vector>
#include <cmath>
#include <queue>
#include <array>
#include <map>
using i64 = long long;
constexpr double eps = 1e-6;
int sgn(double x) {
return x < -eps ? -1 : x > eps;
}
int sgn(i64 x) {
return x < 0 ? -1 : x > 0;
}
template<typename T>
struct Point {
T x, y;
template<class Y>
Point(const Point<Y>& cp):x(cp.x), y(cp.y) {}
Point() : x(0), y(0) {}
Point(T _x, T _y) : x(_x), y(_y) {}
friend std::istream& operator >>(std::istream& is, Point& rhs) { return is >> rhs.x >> rhs.y; }
friend std::ostream& operator <<(std::ostream& os, const Point& rhs) { return os << '(' << rhs.x << ',' << rhs.y << ')'; }
Point operator -(const Point& rhs) const { return {x - rhs.x, y - rhs.y}; }
Point& operator -=(const Point& rhs) { return (*this) = (*this) - rhs; }
Point operator +(const Point& rhs) const { return {x + rhs.x, y + rhs.y}; }
Point& operator +=(const Point& rhs) { return (*this) = (*this) + rhs; }
template<class Y>
Point<double> operator *(const Y& rhs) const { return {x * rhs, y * rhs}; }
template<class Y>
Point<double> operator /(const Y& rhs) { return {x / rhs, y / rhs}; }
friend double abs(const Point& lhs) { return std::sqrt(lhs.x * lhs.x + lhs.y * lhs.y); }
friend i64 abs2(const Point& lhs) { return (lhs.x * lhs.x + lhs.y * lhs.y); }
friend T cross(const Point& lhs, const Point& rhs) { return lhs.x * rhs.y - lhs.y * rhs.x; }
friend T dot(const Point& lhs, const Point& rhs) { return lhs.x * rhs.x + lhs.y * rhs.y; }
friend double angle(const Point& rhs) { return atan2(rhs.x, rhs.y); }
Point rotate90() const { return {y, x}; }
Point<double> rotate(double deg) { return {x * cos(deg) - y * sin(deg), x * sin(deg) + y * cos(deg)}; }
bool operator <(const Point& rhs) const { return sgn(x - rhs.x) == 0 ? sgn(y - rhs.y) < 0 : sgn(x - rhs.x) < 0; }
bool operator ==(const Point& rhs) const { return sgn(x - rhs.x) == 0 && sgn(y - rhs.y) == 0; }
bool up() const { return sgn(y) == 0 ? sgn(x) >= 0 : sgn(y) > 0; }
};
using Pl = Point<i64>;
std::vector<Pl> ConvexHull(std::vector<Pl> points) {
int n = points.size();
std::sort(points.begin(), points.end());
for (auto x: points)std::cout << x << '\n';
std::deque<Pl> dq;
for (auto& point: points) {
while (dq.size() > 1 && sgn(cross(dq[dq.size() - 1] - dq[dq.size() - 2], point - dq[dq.size() - 2])) < 0)dq.pop_back();
dq.push_back(point);
}
for (auto x: dq)std::cerr << x << '\n';
int k = int(dq.size());
for (int i = n - 1; i >= 0; i--) {
while (dq.size() > k && sgn(cross(dq[dq.size() - 1] - dq[dq.size() - 2], points[i] - dq[dq.size() - 2])) < 0)dq.pop_back();
dq.push_back(points[i]);
}
std::vector<Pl> ans(dq.begin(), dq.end());
return ans;
}
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
std::cout.tie(nullptr);
int n;
std::cin >> n;
std::vector<Pl> points(n);
for (int i = 0; i < n; ++i)std::cin >> points[i];
std::vector<std::pair<int, int>> e;
for (int i = 0; i < n; ++i) {
for (int j = 0; j < n; ++j) {
if (i == j)continue;
e.emplace_back(i, j);
}
}
std::sort(e.begin(), e.end(), [&](auto x, auto y) {
Pl v1 = points[x.first] - points[x.second];
Pl v2 = points[y.first] - points[y.second];
return v1.up() ^ v2.up() ? v1.up() > v2.up() : cross(v1, v2) < 0;
});
int ans = 0;
for (int i = 0; i < n; ++i) {
std::vector<int> dp(n, -0x3f3f3f3f);
dp[i] = 0;
for (auto [l, r]: e) {
dp[r] = std::max(dp[r], dp[l] + 1);
}
ans = std::max(ans, dp[i]);
}
std::cout << ans << '\n';
return 0;
}
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