#include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>
#include<cassert>
#include<cmath>
#include<ctime>
#include<iomanip>
#include<numeric>
#include<stack>
#include<queue>
#include<map>
#include<unordered_map>
#include<set>
#include<unordered_set>
#include<bitset>
#include<random>
using namespace std;
void solve()
{
	int N;
	cin >> N;
	set<pair<int,int>> S;
	set<int> X;
	for(int i = 0;i < N;i++)
	{
		int x,y;
		cin >> x >> y;
		bool fn = false;
		for(int i = -19;i < 20;i++)
		{
			int nx = x+i;
			if(!X.count(nx)) continue;
			int ok = y,ng = y+30;
			while(ng-ok > 1)
			{
				int mid = (ok+ng)/2;
				if(i*i + (mid-y)*(mid-y) < 400) ok = mid;
				else ng = mid;
			}
			int uy = ok;
			ok = y,ng = y-30;
			while(ok-ng > 1)
			{
				int mid = (ok+ng)/2;
				if(i*i + (mid-y)*(mid-y) < 400) ok = mid;
				else ng = mid;
			}
			int ly = ok;
			for(int j = ly;j <= uy;j++) if(S.count(make_pair(nx,j))) fn = true;
			if(fn) break;
		}
		if(fn) continue;
		S.insert(make_pair(x,y));
		X.insert(x);
	}
	cout << S.size() << endl;
}
int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int tt = 1;
	//cin >> tt;
	while(tt--) solve();
}