#include <bits/stdc++.h>

int main() {
  
  int N;
  int x, y;
  int x0, x1, y0, y1;

  int* p[2100];
  int ans = 0;
  int temp;

  for(int i = 0; i < 2100; ++i) {
    p[i] = new int[2100];
  }

  for(int i = 0; i < 2100; ++i) {
    for(int j = 0; j < 2100; ++j) {
      p[i][j] = -1;
    }
  }
  
  std::cin >> N;
  for(int i = 0; i < N; ++i) {
    std::cin >> x >> y;
    x += 20;
    y += 20;
    for(int j = -2; j <= 2; ++j) {
      for(int k = -2; k <= 2; ++k) {
	temp = p[x/10 + j][y/10 + k];
	if( p[x/10 + j][y/10 + k] != -1 ) {
	  x0 = temp >> 16;
	  y0 = temp & 0xffff;
	  x1 = x;
	  y1 = y;
	  temp = (x0 - x1) * (x0 - x1) + (y0 - y1) * (y0 - y1);
	  if( temp < 400 ) {
	    goto label_1;
	  }
	}
      }
    }
    p[x/10][y/10] = (x << 16) | y;
    ans += 1;
  label_1:    
    ans = ans;
  }
  
  std::cout << ans << std::endl;
  
  for(int i = 0; i < 2100; ++i) {
    delete [] p[i];
  }
  

  return 0;
}