from collections import defaultdict
from math import *
EPS = 1e-10
INF = float("inf")
N = int(input())
P = [tuple(map(int, input().split())) for i in range(N)]
P.sort(reverse=True)

def cross(i, j, k):
    x0, y0 = P[i]
    x1, y1 = P[j]
    x2, y2 = P[k]
    x1 -= x0
    x2 -= x0
    y1 -= y0
    y2 -= y0
    return x1 * y2 - x2 * y1

def dot(i, j, k):
    x0, y0 = P[i]
    x1, y1 = P[j]
    x2, y2 = P[k]
    x1 -= x0
    x2 -= x0
    y1 -= y0
    y2 -= y0
    return x1 * x2 + y1 * y2

def normal(i, j):
    return atan2(P[j][1] - P[i][1], P[j][0] - P[i][0]) + pi / 2

class Line:
    def __init__(self):
        self.mn = INF
        self.mx = -INF
        self.rev = False
    def update(self, sl):
        if sl < 0:
            sl += 2 * pi
        if self.rev and sl < pi:
            sl += 2 * pi
        if self.mn > sl:
            self.mn = sl
        if self.mx < sl:
            self.mx = sl
        assert pi > self.mx - self.mn >= 0

lines = defaultdict(Line)

for i in range(N - 1):
    if P[i][0] != P[i + 1][0]:
        lines[(1 << i + 1) - 1].rev = True

for i in range(N):
    for j in range(N):
        if i == j:
            continue
        bit1 = 0
        bit2 = 0
        for k in range(N):
            c = cross(i, j, k)
            if c > 0:
                bit1 ^= 1 << k
                bit2 ^= 1 << k
            elif c == 0:
                if dot(i, j, k) > 0:
                    bit1 ^= 1 << k
                else:
                    bit2 ^= 1 << k
        theta = normal(i, j)
        lines[bit1].update(theta - EPS)
        lines[bit2].update(theta + EPS)

lines = list(lines.items())

ans = [False] * (1 << N)
ans[0] = ans[-1] = True

for bit1, _ in lines:
    for bit2, _ in lines:
        ans[bit1 & bit2] = True

def solve(l1, r1, l2, r2, l3, r3):
    if l1 > l2:
        l1, l2 = l2, l1
        r1, r2 = r2, r1
    if l2 > l3:
        l2, l3 = l3, l2
        r2, r3 = r3, r2
    if l1 > l2:
        l1, l2 = l2, l1
        r1, r2 = r2, r1
    if max(r1, r2, r3) - min(l1, l2, l3) < pi:
        return False
    l1 += 2 * pi
    r1 += 2 * pi
    if max(r1, r2, r3) - min(l1, l2, l3) < pi:
        return False
    l2 += 2 * pi
    r2 += 2 * pi
    if max(r1, r2, r3) - min(l1, l2, l3) < pi:
        return False
    return True

L = len(lines)
for i in range(L):
    bit1, l1 = lines[i]
    for j in range(i):
        bit2, l2 = lines[j]
        if not (bit1 & bit2 and bit1 & ~bit2 and ~bit1 & bit2):
            continue
        for k in range(j):
            bit3, l3 = lines[k]
            if not (bit1 & bit2 & bit3 and bit1 & bit2 & ~bit3 and bit1 & ~bit2 & bit3 and ~bit1 & bit2 & bit3):
                continue
            if solve(l1.mn, l1.mx, l2.mn, l2.mx, l3.mn, l3.mx):
                ans[bit1 & bit2 & bit3] = True

print(sum(ans))