import sys from collections import deque from fractions import Fraction as frac input = sys.stdin.readline INF = 10 ** 9 class Vector2: def __init__(self, x: frac, y: frac): self.x = x self.y = y 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) class Line: def __init__(self, a: frac, b:frac, c:frac): self.a = a self.b = b self.c = c 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)) def normalize_vector(v: Vector2) -> Vector2: assert(v.x != 0 or v.y != 0) norm = v.x ** 2 + v.y ** 2 return Vector2(v.x * abs(v.x) / norm, v.y * abs(v.y) / norm) def calc_line(one: Vector2, other: Vector2) -> Line: 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) def calc_intersection(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1 if(N == 1): print(1) exit(0) # 各点に番号付け ph = {} pt_id = 0 for p in P: ph[p] = pt_id pt_id += 1 # 有り得る直線を調べて番号付け ln_id = 0 lh = {} for i in range(N - 1): for j in range(i + 1, N): p1, p2 = P[i], P[j] l = calc_line(p1, p2) if(l in lh): continue lh[l] = ln_id ln_id += 1 # 有り得る交点を調べて番号付け lis = list(lh.keys()) for i in range(ln_id - 1): for j in range(i + 1, ln_id): l1, l2 = lis[i], lis[j] p = calc_intersection(l1, l2) if(p is None or p in ph): continue P.append(p) ph[p] = pt_id pt_id += 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]*pt_id for _ in [0]*pt_id] for i in range(pt_id - 1): for j in range(i + 1, pt_id): if(calc_line(P[i],P[j]) not in lh): continue vec_lis[i][j] = normalize_vector(P[j] - P[i]) vec_lis[j][i] = normalize_vector(P[i] - P[j]) # グラフ探索 dp = [[[INF]*pt_id for _ in [0]*pt_id] for _ in [0]*(1 << N)] que = deque([]) for i in range(N): que.append((0, 1 << i, i, i)) dp[1 << i][i][i] = 0 goal = (1 << N) - 1 ans = INF while(que): c, b, lv, v = que.popleft() if(c > dp[b][lv][v]): continue if(b == goal): ans = c break for nv in range(pt_id): if(v == nv or min(v, nv) >= N or (vec_lis[v][nv] is None)): continue nb = b | (1 << nv) if(nv < N) else b nc = c if(lv == v or vec_lis[lv][v] != vec_lis[v][nv]): nc += 1 if(nc >= dp[nb][v][nv]): continue dp[nb][v][nv] = nc if(nc == c): que.appendleft((nc, nb, v, nv)) else: que.append((nc, nb, v, nv)) print(ans)