import sys
input = sys.stdin.readline
from collections import *

N = int(input())
XY = []
for x in range(-20, 21):
    for y in range(-20, 21):
        if x ** 2 + y ** 2 < 400:
            XY.append((x, y))

D = defaultdict(set)
ans = 0
for i in range(N):
    X, Y = map(int, input().split())
    for x, y in XY:
        if Y + y in D[X + x]:
            break
    else:
        D[X].add(Y)
        ans += 1

print(ans)