import std.conv, std.functional, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.container, std.math, std.numeric, std.range, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


enum long R = 10;
enum long A = 14;
enum LIM = cast(int)(20000 / A) + 1;

int N;
long[] X, Y;

void main() {
  try {
    for (; ; ) {
      N = readInt();
      X = new long[N];
      Y = new long[N];
      foreach (i; 0 .. N) {
        X[i] = readLong();
        Y[i] = readLong();
      }
      
      auto js = new int[][](LIM, LIM);
      foreach (e; 0 .. LIM) {
        js[e][] = -1;
      }
      
      int ans;
      foreach (i; 0 .. N) {
        const e0 = cast(int)(X[i] / A);
        const f0 = cast(int)(Y[i] / A);
        foreach (e; e0 - 2 .. e0 + 2 + 1) foreach (f; f0 - 2 .. f0 + 2 + 1) {
          if (0 <= e && e < LIM && 0 <= f && f < LIM) {
            const j = js[e][f];
            if (j != -1) {
              if ((X[i] - X[j])^^2 + (Y[i] - Y[j])^^2 < (2 * R)^^2) {
                goto found;
              }
            }
          }
        }
        ++ans;
        assert(js[e0][f0] == -1);
        js[e0][f0] = i;
       found:
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}