#include<iostream>
using namespace std;

int sum[1000];

int main()
{
	int n, a[1000][2], m = 0;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		for (int j = 0; j < 3; j++)
		{
			cin >> a[i][j];
		}
	}
	for (int k = 0; k < n-1; k++)
	{
		for (int h = 0; h < 3; h++)
		{
			sum[k] += a[k][h];
			if (abs(a[k][h] - a[k + 1][h]) <= 5 && abs(sum[k]-sum[k+1]) <= 10)
			{
				m++;
			}
		}
	}
	cout << m << endl;
	system("pause");
	return 0;
}