import sys
input = sys.stdin.readline

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))

S = set()
for i in range(N):
    X, Y = map(int, input().split())
    for x, y in XY:
        if (X + x, Y + y) in S:
            break
    else:
        S.add((X, Y))

print(len(S))