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