#include <bits/stdc++.h>
const double EPS = 1e-5;
enum POSITION {
  ONLINE_FRONT = -2,
  CLOCKWISE,
  ON_SEGMENT,
  COUNTER_CLOCKWISE,
  ONLINE_BACK
};
struct Point {
  double x, y;
  Point(const double d = 0.0) : x(d), y(d) {}
  Point(const double x, const double y) : x(x), y(y) {}
};
struct Segment {
  Point initial, terminal;
  Segment(const Point& initial, const Point& terminal)
      : initial(initial), terminal(terminal) {}
  Segment(const double x1, const double y1, const double x2, const double y2)
      : initial(x1, y1), terminal(x2, y2) {}
};
struct Line {
  Point initial, terminal;
  Line(const Point& initial, const Point& terminal)
      : initial(initial), terminal(terminal) {}
  Line(const double x1, const double y1, const double x2, const double y2)
      : initial(x1, y1), terminal(x2, y2) {}
  Line(const Segment& s) : initial(s.initial), terminal(s.terminal) {}
};
bool relative_equal(const double d1, const double d2) {
  return d1 == 0 ? std::abs(d2) < EPS : std::abs((d1 - d2) / d1) < EPS;
}
bool operator==(const Point& lhs, const Point& rhs) {
  return relative_equal(lhs.x, rhs.x) && relative_equal(lhs.y, rhs.y);
}
bool operator<(const Point& lhs, const Point& rhs) {
  return relative_equal(lhs.x, rhs.x) ? lhs.y < rhs.y : lhs.x < rhs.x;
}
bool operator>(const Point& lhs, const Point& rhs) {
  return relative_equal(lhs.x, rhs.x) ? lhs.y > rhs.y : lhs.x > rhs.x;
}
bool operator!=(const Point& lhs, const Point& rhs) { return !(lhs == rhs); }
bool operator<=(const Point& lhs, const Point& rhs) { return !(lhs > rhs); }
bool operator>=(const Point& lhs, const Point& rhs) { return !(lhs < rhs); }
const Point operator+(const Point& lhs, const Point& rhs) {
  return Point(lhs.x + rhs.x, lhs.y + rhs.y);
}
const Point operator-(const Point& lhs, const Point& rhs) {
  return Point(lhs.x - rhs.x, lhs.y - rhs.y);
}
const Point operator*(const Point& lhs, const Point& rhs) {
  return Point(lhs.x * rhs.x, lhs.y * rhs.y);
}
const Point operator/(const Point& lhs, const Point& rhs) {
  return Point(lhs.x / rhs.x, lhs.y / rhs.y);
}
const Point operator-(const Point& p) { return Point(-p.x, -p.y); }
double abs(const Point& p) { return std::hypot(p.x, p.y); }
double norm(const Point& p) { return p.x * p.x + p.y * p.y; }
double dot(const Point& a, const Point& b) { return a.x * b.x + a.y * b.y; }
double cross(const Point& a, const Point& b) { return a.x * b.y - a.y * b.x; }
bool parallel(const Line& l1, const Line& l2) {
  return relative_equal(
      0.0, cross(l2.terminal - l2.initial, l1.terminal - l1.initial));
}
bool orthogonal(const Line& l1, const Line& l2) {
  return relative_equal(
      0.0, dot(l2.terminal - l2.initial, l1.terminal - l1.initial));
}
POSITION ccw(const Point& a, const Point& b, const Point& p) {
  Point v1 = b - a;
  Point v2 = p - a;
  if (cross(v1, v2) >= EPS) return COUNTER_CLOCKWISE;
  if (cross(v1, v2) <= -EPS) return CLOCKWISE;
  if (dot(v1, v2) <= -EPS) return ONLINE_BACK;
  if (norm(v1) < norm(v2)) return ONLINE_FRONT;
  return ON_SEGMENT;
}
bool intersect(const Point& p1, const Point& p2) { return p1 == p2; }
bool intersect(const Point& p, const Segment& s) {
  return abs(p - s.initial) + abs(p - s.terminal) -
             abs(s.initial - s.terminal) <=
         EPS;
}
bool intersect(const Segment& s, const Point& p) { return intersect(p, s); }
bool intersect(const Point& p, const Line& l) {
  return !parallel(Line(p, l.initial), Line(p, l.terminal));
}
bool intersect(const Line& l, const Point& p) { return intersect(p, l); }
bool intersect(const Segment& s1, const Segment& s2) {
  return ccw(s1.initial, s1.terminal, s2.initial) *
                 ccw(s1.initial, s1.terminal, s2.terminal) <=
             0 &&
         ccw(s2.initial, s2.terminal, s1.initial) *
                 ccw(s2.initial, s2.terminal, s1.terminal) <=
             0;
}
bool intersect(const Segment& s, const Line& l) {
  auto v1 = l.terminal - l.initial;
  auto v2 = s.initial - l.initial;
  auto v3 = s.terminal - l.initial;
  return cross(v1, v2) * cross(v1, v3) <= EPS;
}
bool intersect(const Line& l, const Segment& s) { return intersect(s, l); }
bool intersect(const Line& l1, const Line& l2) {
  return !parallel(l1, l2) || intersect(l1.initial, l2);
}
Point projection(const Point& p, const Line& l) {
  auto v = l.initial - l.terminal;
  return l.initial + dot(p - l.initial, v) / norm(v) * v;
}
Point projection(const Line& l, const Point& p) { return projection(p, l); }
Point reflection(const Point& p, const Line& l) {
  return p + 2 * (projection(p, l) - p);
}
Point reflection(const Line& l, const Point& p) { return reflection(p, l); }
double distance(const Point& p1, const Point& p2) {
  auto p = p1 - p2;
  return hypot(p.x, p.y);
}
double distance(const Point& p, const Segment& s) {
  auto r = projection(s, p);
  return intersect(r, s)
             ? distance(p, r)
             : std::min(distance(p, s.initial), distance(p, s.terminal));
}
double distance(const Segment& s, const Point& p) { return distance(p, s); }
double distance(const Point& p, const Line& l) {
  return distance(p, projection(p, l));
}
double distance(const Line& l, const Point& p) { return distance(p, l); }
double distance(const Segment& s1, const Segment& s2) {
  return intersect(s1, s2)
             ? 0.0
             : std::min({distance(s1, s2.initial), distance(s1, s2.terminal),
                         distance(s2, s1.initial), distance(s2, s1.terminal)});
}
double distance(const Segment& s, const Line& l) {
  return intersect(s, l)
             ? 0.0
             : std::min(distance(s.initial, l), distance(s.terminal, l));
}
double distance(const Line& l, const Segment& s) { return distance(s, l); }
double distance(const Line& l1, const Line& l2) {
  return intersect(l1, l2) ? 0.0 : distance(l1.initial, l2);
}
const Point crosspoint(const Line& l1, const Line& l2) {
  assert(intersect(l1, l2));
  if (parallel(l1, l2)) return l1.initial;
  double A = cross(l1.terminal - l1.initial, l2.terminal - l2.initial);
  double B = cross(l1.terminal - l1.initial, l1.terminal - l2.initial);
  return l2.initial + B / A * (l2.terminal - l2.initial);
}
const Point crosspoint(const Segment& s, const Line& l) {
  assert(intersect(s, l));
  if (parallel(s, l)) return s.initial;
  return crosspoint(Line(s), l);
}
const Point crosspoint(const Line& l, const Segment& s) {
  return crosspoint(s, l);
}
const Point crosspoint(const Segment& s1, const Segment& s2) {
  assert(intersect(s1, s2));
  if (parallel(s1, s2)) {
    if (intersect(s1.initial, s2)) return s1.initial;
    if (intersect(s1.terminal, s2)) return s1.terminal;
    if (intersect(s2.initial, s1)) return s2.initial;
    if (intersect(s2.terminal, s1)) return s2.terminal;
  }
  return crosspoint(Line(s1), Line(s2));
}
std::ostream& operator<<(std::ostream& os, const Point& p) {
  os << "point: ";
  os << "(" << p.x << "," << p.y << ")";
  return os;
}
std::ostream& operator<<(std::ostream& os, const Segment& s) {
  os << "segment: ";
  os << s.initial << " - " << s.terminal;
  return os;
}
std::ostream& operator<<(std::ostream& os, const Line& l) {
  os << "line: ";
  os << l.initial << " - " << l.terminal;
  return os;
}
class Polygon {
 public:
  void add(const Point& p);
  void clear();
  int size() const;
  Point vertex(const int n) const;
  Segment edge(const int n) const;
  const std::vector<Point>& vertex() const;
  const std::vector<Segment>& edge() const;
  bool touch(const Point& p) const;
  bool intersect(const Point& p) const;
  double area() const;
  bool convex() const;
  const Polygon convex_hull() const;
  double convex_diameter() const;
  const Polygon convex_cut(const Line& l) const;

 private:
  std::vector<Point> vertex_;
  std::vector<Segment> edge_;
};
void Polygon::add(const Point& p) {
  if (!vertex_.empty()) {
    if (!edge_.empty()) edge_.pop_back();
    edge_.push_back(Segment(vertex_.back(), p));
    edge_.push_back(Segment(p, vertex_.front()));
  }
  vertex_.push_back(p);
}
void Polygon::clear() {
  vertex_.clear();
  edge_.clear();
};
int Polygon::size() const { return vertex_.size(); }
Point Polygon::vertex(const int n) const { return vertex_.at(n); }
Segment Polygon::edge(const int n) const { return edge_.at(n); }
const std::vector<Point>& Polygon::vertex() const { return vertex_; }
const std::vector<Segment>& Polygon::edge() const { return edge_; }
bool Polygon::touch(const Point& p) const {
  return std::any_of(std::begin(edge()), std::end(edge()),
                     [=](const Segment& s) {
                       return ccw(s.initial, s.terminal, p) == ON_SEGMENT;
                     });
}
bool Polygon::intersect(const Point& p) const {
  bool in = false;
  for (const auto& e : edge()) {
    if (::intersect(p, e)) return true;
    Point a = e.initial - p;
    Point b = e.terminal - p;
    if (a.y > b.y) std::swap(a, b);
    if (a.y < EPS && EPS <= b.y && cross(a, b) < EPS) in = !in;
  }
  return in;
}
double Polygon::area() const {
  return std::abs(std::accumulate(std::begin(edge()), std::end(edge()), 0.0,
                                  [=](const double sum, const Segment& e) {
                                    return sum + cross(e.initial, e.terminal);
                                  })) /
         2.0;
}
bool Polygon::convex() const {
  bool positive = false;
  bool negative = false;
  for (int i = 0; i < size(); ++i) {
    auto position =
        ccw(vertex(i), vertex((i + 1) % size()), vertex((i + 2) % size()));
    positive |= position == CLOCKWISE;
    negative |= position == COUNTER_CLOCKWISE;
    if (negative && positive) return false;
  }
  return true;
}
const Polygon Polygon::convex_hull() const {
  auto original = vertex();
  std::sort(std::begin(original), std::end(original));
  original.insert(std::end(original), original.rbegin() + 1, original.rend());
  std::vector<Point> point;
  for (const auto& p : original) {
    while (point.size() >= 2 &&
           ccw(point[point.size() - 2], point.back(), p) == CLOCKWISE)
      point.pop_back();
    point.push_back(p);
  }
  Polygon convex_hull;
  point.pop_back();
  for (const auto& p : point) convex_hull.add(p);
  return convex_hull;
}
double Polygon::convex_diameter() const {
  auto point = vertex();
  int p, q, start_p, start_q, max_p, max_q;
  p = start_p = max_p =
      std::min_element(std::begin(point), std::end(point)) - std::begin(point);
  q = start_q = max_q =
      std::max_element(std::begin(point), std::end(point)) - std::begin(point);
  double max_d = norm(vertex(p) - vertex(q));
  do {
    if (cross(vertex((p + 1) % size()) - vertex(p),
              vertex((q + 1) % size()) - vertex(q)) >= 0)
      q = (q + 1) % size();
    else
      p = (p + 1) % size();
    if (norm(vertex(p) - vertex(q)) > max_d) {
      max_d = norm(vertex(p) - vertex(q));
      max_p = p;
      max_q = q;
    }
  } while (start_p != q || start_q != p);
  return std::sqrt(max_d);
}
const Polygon Polygon::convex_cut(const Line& l) const {
  Polygon result;
  for (const auto& e : edge()) {
    if (ccw(l.initial, l.terminal, e.initial) == COUNTER_CLOCKWISE)
      result.add(e.initial);
    if (::intersect(e, l)) result.add(crosspoint(e, l));
  }
  return result;
}
using namespace std;
int solve(const vector<Point>& point) {
  int res = point.size();
  Polygon polygon;
  for (const auto& p : point) polygon.add(p);
  vector<Segment> edge;
  for (int i = 0; i < point.size(); ++i)
    edge.push_back(Segment(point[i], point[(i + 1) % point.size()]));
  for (int i = 0; i < point.size(); ++i)
    for (int j = i + 1; j < point.size(); ++j) {
      Segment s(point[i], point[j]);
      for (auto it = begin(edge); it != end(edge); ++it) {
        if (intersect(point[i], *it)) continue;
        if (intersect(point[j], *it)) continue;
        if (!intersect(s, *it)) continue;
        auto cp = crosspoint(s, *it);
        if (cp == point[i] || cp == point[j]) continue;
        if (cp == it->initial || cp == it->terminal) continue;
        Segment s1(it->initial, cp), s2(cp, it->terminal);
        it = edge.erase(it);
        it = edge.insert(it, s1);
        ++it;
        it = edge.insert(it, s2);
      }
    }
  map<tuple<int, int>, bool> memo;
  for (int bit = 1; bit < (1 << point.size()); ++bit) {
    set<int> vertex;
    for (int i = 0; i < point.size(); ++i)
      if ((bit >> i) & 1) vertex.insert(i);
    bool ok = true;
    for (int i = 0; i < edge.size(); ++i) {
      bool covered = false;
      for (const auto& v : vertex) {
        if (memo.count(tuple<int, int>(i, v))) {
          if (!memo[tuple<int, int>(i, v)]) continue;
          covered = true;
          break;
        }
        auto g = (point[v] + edge[i].initial + edge[i].terminal) / 3.0;
        if (!polygon.intersect(g)) {
          memo[tuple<int, int>(i, v)] = false;
          continue;
        }
        Segment s(point[v], (edge[i].terminal + edge[i].initial) / 2.0);
        bool f = true;
        for (int j = 0; j < edge.size(); ++j) {
          if (i == j) continue;
          if (!intersect(s, edge[j])) continue;
          auto cp = crosspoint(s, edge[j]);
          if (parallel(s, edge[j])) continue;
          if (cp == s.initial || cp == s.terminal) continue;
          if (cp == edge[j].initial || cp == edge[j].terminal) continue;
          f = false;
          break;
        }
        if (f) covered = true;
        memo[tuple<int, int>(i, v)] = f;
      }
      if (!covered) {
        ok = false;
        break;
      }
    }
    if (ok)
      if (vertex.size() < res) res = vertex.size();
  }
  return res;
}
int main() {
  int n;
  while (cin >> n, n) {
    vector<Point> point(n);
    for (auto& p : point) cin >> p.x >> p.y;
    cout << solve(point) << endl;
  }
}
