#include<bits/stdc++.h>
using namespace std;
int a[110000],b[100100],c[100010];
int n,p;
int main(){
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>a[i];
		cin>>b[i];
		cin>>c[i];
	}
	for(int i=0;i<n;i++){
		if(abs(a[i]-a[i+1])<=5&&abs(b[i]-b[i+1])<=5&&abs(c[i]-c[i+1])<=5&&abs(a[i]+b[i]+c[i]-a[i+1]-b[i+1]-c[i+1]<=10)) p+=1;
	}
	cout<<p;
	return 0;
}