#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
#include <set>
using namespace std;

#define REP(i,s,e) for (i = s; i <= e; i++)
#define rep(i,n) REP (i,0,(int)(n)-1)
#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP (i,(int)(n)-1,0)
#define INF (int)1e8
#define MOD (int)(1e9+7)

typedef long long ll;

set<int> coin[20001];

int main(void) {
    int i, n;
    scanf("%d",&n);
    rep (i,n) {
        int X, Y;
        scanf("%d%d",&X,&Y);
        int x;
        bool ok = true;
        REP (x,max(X-20,0),min(X+20,20000)) {
            for (int j = max(Y-20,0); j <= min(Y + 20,20000); j++) {
                auto py = coin[x].lower_bound(j);
                if (py != coin[x].end()) {
                    int y = *py;
                    ok &= (x - X) * (x - X) + (y - Y) * (y - Y) >= 400;
                }
            }
        }
        if (ok) coin[X].insert(Y);
    }
    int ans = 0;
    REP (i,0,20000) ans += coin[i].size();
    printf("%d\n",ans);
    return 0;
}