from __future__ import annotations import sys from collections import deque from itertools import combinations from fractions import Fraction as frac input = sys.stdin.readline class Vector2: def __init__(self, x, y): self.x = x self.y = y def __str__(self): return str((self.x, self.y)) __repr__ = __str__ def __eq__(self, other): return (self.x == other.x and self.y == other.y) def __hash__(self): return hash((self.x, self.y)) def __sub__(self, other): return Vector2(other.x - self.x, other.y - self.y) def normalize(self) -> Vector2: assert(self.x != 0 or self.y != 0) norm = self.x ** 2 + self.y ** 2 self.x *= abs(self.x) / norm self.y *= abs(self.y) / norm return self class Line: def __init__(self, a, b, c): self.a = a self.b = b self.c = c def __str__(self): return str((self.a, self.b, self.c)) __repr__ = __str__ def __eq__(self, other): return (self.a == other.a and self.b == other.b and self.c == other.c) def __hash__(self): return hash((self.a, self.b, self.c)) @classmethod def calc_line(cls, one: Vector2, other: Vector2) -> Line: if(one == other): return None x1 = one.x; y1 = one.y x2 = other.x; y2 = other.y if(x1 == x2): return Line(1, 0, x1) a = (y1 - y2) / (x1 - x2) c = y1 - a * x1 return Line(-a, 1, c) @classmethod def calc_intersection(cls, one: Line, other: Line) -> Vector2: p = one.a * other.b - other.a * one.b if(p == 0): return None q = other.b * one.c - one.b * other.c x = q / p y = (other.c - other.a * x) / other.b if(one.b == 0) else (one.c - one.a * x) / one.b return Vector2(x, y) """ Main Code """ # 入力 N = int(input()) P = [Vector2(*map(frac, input().split())) for _ in [0] * N] # 点が 1 個のときは必ず答えは 1 if(N == 1): print(1) exit(0) # 任意の 2 点に関する直線を調べてsetに追加 line_set = set([]) for p1, p2 in combinations(P, 2): line_set.add(Line.calc_line(p1, p2)) # 任意の 2 直線の交点を調べてlist, setに追加 point_set = set(P) point_num = N for l1, l2 in combinations(line_set, 2): p = Line.calc_intersection(l1, l2) if(p is None or p in point_set): continue point_set.add(p) P.append(p) point_num += 1 # 任意の2点について、2点から構成されるベクトルを調べて正規化 vec_lis = [[None]*point_num for _ in [0]*point_num] for i in range(point_num - 1): for j in range(i + 1, point_num): if(Line.calc_line(P[i], P[j]) not in line_set): continue vec_lis[i][j] = (P[i] - P[j]).normalize() vec_lis[j][i] = (P[j] - P[i]).normalize() # グラフ探索 mbit = 1 << N goal = mbit - 1 dp = [[[N]*point_num for _ in [0]*point_num] for _ in [0]*mbit] que = deque([]) ans = N for i in range(N): dp[1 << i][i][i] = 0 que.append((1 << i, i, i, 0)) while(que): b_now, v_prev, v_now, c_now = que.popleft() if(c_now > dp[b_now][v_prev][v_now]): continue if(b_now == goal): ans = c_now break for v_next in range(point_num): if(v_next in [v_prev, v_now] or min(v_now, v_next) >= N): continue if(vec_lis[v_now][v_next] is None): continue b_next = b_now | (1 << v_next) if(v_next < N) else b_now c_next = c_now + (v_prev == v_now or vec_lis[v_prev][v_now] != vec_lis[v_now][v_next]) if(c_next >= dp[b_next][v_now][v_next]): continue dp[b_next][v_now][v_next] = c_next if(c_now == c_next): que.appendleft((b_next, v_now, v_next, c_next)) else: que.append((b_next, v_now, v_next, c_next)) print(ans)