def dist(ax, ay, bx, by):
    return (ax - bx) ** 2 + (ay - by) ** 2
    
N = int(raw_input())
X = [set([]) for i in xrange(20021)]
Y = [set([]) for i in xrange(20021)]
ans = 0
for loop in xrange(N):
    x, y = map(int, raw_input().split())
    cand = X[i] & Y[i]
    for cx, cy in cand:
        if dist(x, y, cx, cy) < 400:
            break
    else:
        for xi in xrange(max(0, x - 20), x + 20):
            X[xi].add((x, y))
        for yi in xrange(max(0, y - 20), y + 20):
            Y[yi].add((x, y))
        ans +=1
print ans