#include<bits/stdc++.h> using namespace std; int main() { int n,a[1100],b[1100],c[1100],sum=1; cin>>n; for(int i=1;i<=n;i++) { cin>>a[n]>>b[n]>>c[n]; } for(int i=1;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]))) { sum++; } } cout<<sum;

return 0;

}