#include <bits/stdc++.h>

using namespace std;

using i64 = long long;
using db = long double;

db eps = 1e-10;
db pi = acos(-1);

int sign(db a) {
    return a < -eps ? -1 : a > eps;
}

int cmp(db a, db b) {
    return sign(a - b);
}

struct Points {
    db x, y;
    
    Points(db _x = 0., db _y = 0.) : x(_x), y(_y) {}
    
    int operator<(const Points &rhs) const {
        int c = cmp(x, rhs.x);
        if (c) {
            return c == -1;
        }
        return cmp(y, rhs.y) == -1;
    }
};

Points operator+(Points a, Points b) {
    return Points(a.x + b.x, a.y + b.y);
}

Points operator-(Points a, Points b) {
    return Points(a.x - b.x, a.y - b.y);
}

db dot(Points a, Points b) {
    return a.x * b.x + a.y * b.y;
}

db Cross(Points a, Points b) {
    return a.x * b.y - a.y * b.x;
}

db len(Points a) {
    return sqrt(dot(a, a));
}

int quad(Points a) {
    return sign(a.y) == 1 || (sign(a.y) == 0 && sign(a.x) >= 0);
}

db Cross(Points p1, Points p2, Points p3) {
    return ((p2.x - p1.x) * (p3.y - p1.y) - (p3.x - p1.x) * (p2.y - p1.y));
}

int crossOp(Points p1, Points p2, Points p3) {
    return sign(Cross(p1, p2, p3));
}

bool isMiddle(db a, db m, db b) {
    return sign(a - m) == 0 || sign(b - m) == 0 || (a < m != b < m);
}

bool isMiddle(Points a, Points m, Points b) {
    return isMiddle(a.x, m.x, b.x) && isMiddle(a.y, m.y, b.y);
}

bool OnSeg(Points p1, Points p2, Points q) {
    return crossOp(p1, p2, q) == 0 && isMiddle(p1, q, p2);
}

vector<Points> convex_hell(vector<Points> &pts) {
    sort(pts.begin(), pts.end());
    int n = pts.size(), m = 0;
    vector<Points> ch;
    for (int i = 0; i < n; i++) {
        while (m > 1 && Cross(ch[m - 1] - ch[m - 2], pts[i] - ch[m - 2]) <= 0) {
            ch.pop_back();
            m--;
        }
        ch.push_back(pts[i]);
        m++;
    }
    int k = m;
    for (int i = n - 2; i >= 0; i--) {
        while (m > k && Cross(ch[m - 1] - ch[m - 2], pts[i] - ch[m - 2]) <= 0) {
            ch.pop_back();
            m--;
        }
        ch.push_back(pts[i]);
        m++;
    }
    if (n > 1) {
        ch.pop_back();
        m--;
    }
    return ch;
}

int pointsInPoly(vector<Points> &p, Points a) {
    int n = p.size(), ret = 0;
    for (int i = 0; i < n; i++) {
        Points u = p[i], v = p[(i + 1) % n];
        if (OnSeg(u, v, a)) {
            assert(0);
            return 1;
        }
        if (cmp(u.y, v.y) <= 0) {
            swap(u, v);
        }
        if (cmp(a.y, u.y) > 0 || cmp(a.y, v.y) <= 0) {
            continue;
        }
        ret ^= crossOp(a, u, v) > 0;
    }
    return ret * 2;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int n;
    cin >> n;
    vector<Points> pts;
    for (int i = 1; i <= n; i++) {
        int x, y;
        cin >> x >> y;
        pts.push_back(Points(x, y));
    }
    auto ch = convex_hell(pts);
    vector<Points> notOnConvVec;
    map<Points, bool> onConv;
    for (int i = 0; i < ch.size(); i++) {
        onConv[ch[i]] = 1;
    }
    for (int i = 0; i < pts.size(); i++) {
        if (!onConv.count(pts[i])) {
            notOnConvVec.push_back(pts[i]);
        }
    }
    if (notOnConvVec.size() == 0) {
        cout << 1 << "\n";
        return 0;
    }
    int ans = 1;
    auto process = [&](vector<Points> &pts, Points a, Points b) {
        for (int i = 0; i < pts.size(); i++) {
            pts[i] = pts[i] - a;
        }
        sort(pts.begin(), pts.end(), [](Points a, Points b) {
            int qa = quad(a), qb = quad(b);
            if (qa != qb) {
                return qa < qb;
            } else {
                return sign(Cross(a, b)) > 0;
            }
        });
        for (int i = 0; i < pts.size(); i++) {
            pts[i] = pts[i] + a;
        }
    };
    for (int i = 0; i < ch.size(); i++) {
        process(notOnConvVec, ch[i], ch[(i + 1) % ch.size()]);
        vector<Points> tmp;
        tmp.push_back(ch[i]);
        tmp.push_back(ch[(i + 1) % ch.size()]);
        tmp.push_back(notOnConvVec[0]);
        ans++;
        for (int j = 1; j < notOnConvVec.size(); j++) {
            auto las = tmp.back();
            tmp.pop_back();
            tmp.push_back(notOnConvVec[j]);
            if (!(pointsInPoly(tmp, las) >= 1)) {
                ans++;
                tmp.pop_back();
                tmp.push_back(notOnConvVec[j]);
            } else {
                tmp.pop_back();
                tmp.push_back(las);
            }
        }
    }
    cout << ans << "\n";
    return 0;
}