#import<bits/stdc++.h>
#define f(x)(x)*(x)
using namespace std;int x,y,z=1e5;main(){set<int>a;for(cin>>x;cin>>x>>y;)for(auto i=a.lower_bound((x-20)*z),j=a.upper_bound((x+20)*z);i==j?a.insert(x*z+y),0:f(x-*i/z)+f(y-*i%z)>=400;++i);cout<<a.size();}