// yukicoder: No.202 1円玉投げ
// 2019.6.28 bal4u

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#if 1
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif
int in()
{
	int n = 0, c = gc();
	do n = 10 * n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

typedef struct { int x, y, id; } T;
T t[100005]; int N;
int id[100005];
char f[100005];

int cmp(const void *a, const void *b) {
	int t = ((T *)a)->x - ((T *)b)->x;
	if (t) return t;
	return ((T *)a)->y - ((T *)b)->y;
}

// 見つからなければ、一つ大きい要素を返す。つまり、 >= x
int low_bound(int x)
{
	int m, l = 0, r = N;

    while (l < r) {
        m = (l+r) >> 1;
        if (t[m].x < x) l = m + 1; else r = m;
    }
	return l;
}

// 見つからなければ、一つ小さい要素を返す
int upper_bound(int x)
{
	int m, l = 0, r = N;

    while (l < r) {
        m = (l+r) >> 1;
        if (t[m].x <= x) l = m + 1; else r = m;
    }
	return l-1;
}

int overlap(int x1, int x2, int y1, int y2) {
	int dx, dy;
	dx = x1 - x2;
	if (dx < 0) dx = -dx;
	if (dx >= 20) return 0;
	dy = y1 - y2;
	if (dy < 0) dy = -dy;
	if (dy >= 20) return 0;
	return (dx*dx + dy*dy) < 400;
}

int main()
{
	int i, j, x, y, r, ans;

	ans = N = in();
	for (i = 0; i < N; i++) t[i].x = in(), t[i].y = in(), t[i].id = i;
	memset(f, 1, N);
	qsort(t, N, sizeof(T), cmp);
	for (i = 0; i < N; i++) id[t[i].id] = i;
	
	for (i = 0; i < N; i++) if (f[i]) {
		x = t[id[i]].x;
		j = low_bound(x-20), r = upper_bound(x+20);
		while (j <= r) {
			y = t[j].id;
			if (f[y] && y != i) {
				if (overlap(x, t[j].x, t[id[i]].y, t[j].y)) f[y] = 0, ans--;
			}
			j++;
		}
	}
	printf("%d\n", ans);
	return 0;
}