#include <iostream>
#include <sstream>
#include <string>
#include <stl.h>
#include <climits>
#include <complex>
#include <cmath>
#include <cctype>

using namespace std;

#define ERROR 1e-10
#define cmp_t complex<double>
#define re real()
#define im imag()

bool operator<(const cmp_t& a,const cmp_t& b)
{
    return a.re < b.re-ERROR || (a.re < b.re+ERROR && a.im < b.im-ERROR);
}

bool GetCircleCrossPoint(cmp_t& a1,cmp_t& a2,
			 cmp_t o1,double r1,cmp_t o2,double r2)
{
    // I'm Sorry but we can't go public. This is our private library.
}

int Count(cmp_t o,vector<cmp_t>& points)
{
    int ans = 0;
    vector<cmp_t>::iterator p = upper_bound(points.begin(),points.end(),cmp_t(o.re-1-ERROR,0));
    vector<cmp_t>::iterator q = lower_bound(points.begin(),points.end(),cmp_t(o.re+1+ERROR,0));
    while(p <= q)
    {
	if(abs(*p - o) < 1+ERROR)ans++;
	p++;
    }
    return ans;
}

int Solve(vector<cmp_t>& points)
{
    int ans = 1,n=points.size();
    sort(points.begin(),points.end());
    for(int i = 0 ; i < n ; i++)
	for(int j = i+1 ; j < n ; j++)
	    if(points[i].re+2 > points[j].re+ERROR)
	    {
		cmp_t p1,p2;
		if(GetCircleCrossPoint(p1,p2,points[i],1,points[j],1))
		{
		    ans = max(ans,max(Count(p1,points),Count(p2,points)));
		}
	    }
    return ans;
}

int main()
{
    int n;
    while(cin >> n , n)
    {
	double x,y;
	vector<cmp_t> points;
	while(n--)
	{
	    cin >> x >> y;
	    points.push_back(cmp_t(x,y));
	}
	cout << Solve(points) << endl;
    }
    return 0;
}