#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
#include <string>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <climits>
#include <complex>
using namespace std;
typedef complex<double> point;
#define EPS 0.0001

int count( point p, const vector<point>& pts )
{
  int n = 0;
  for( int i=0; i!=pts.size(); ++i )
    if( abs(pts[i]-p) <= 1.0+EPS )
      ++n;
  return n;
}

pair<point, point> center_of_circle(point a, point b)
{
  pair<point, point> answer;
  {
    point     n( imag(a-b), real(b-a) );
    double absn = abs(n); 
    answer.first = (a+b)/2 + sqrt(1-absn*absn/4)*n/absn;
  }
  {
    point     n( imag(a-b), real(b-a) );
    n = -n;
    double absn = abs(n); 
    answer.second = (a+b)/2 + sqrt(1-absn*absn/4)*n/absn;
  }
  return answer;
}


int solve( const vector<point>& pts )
{
  int maxInclude = 1;
  for( int i=0; i!=pts.size(); ++i )
    {
      point p1 = pts[i];
      for( int j=i+1; j!=pts.size(); ++j )
	{
	  point p2 = pts[j];
	  if( abs(p1-p2) > 2.0 )
	    continue;

	  // count the inclusion
	  pair<point, point> c = center_of_circle( p1, p2 );
	  //cout << c.first << ',' << c.second << endl;
	  int n1 = count( c.first, pts );
	  int n2 = count( c.second, pts );
	  if( maxInclude < n1 ) maxInclude = n1;
	  if( maxInclude < n2 ) maxInclude = n2;
	}
    }
  return maxInclude;
}

int main()
{
  int N;
  while( cin>>N, N )
    {
      vector<point> pts;
      while( N-- )
	{
	  double x, y;
	  cin >> x >> y;
	  pts.push_back( point(x,y) );
	}

      cout << solve(pts) << endl;
    }
}