#include <iostream>
#include <algorithm>
#include <cmath>
using namespace std;

int main()
{
	int n;
	int count = 0;
	int count1 = 0;
	int a[1000][4] = { 100010 };
	cin >> n;
	for (int i = 0;i <= n - 1;i++)
	{
		for (int j = 0;j <= 2;j++)
		{
			cin >> a[i][j];
		}
	}
	int i = 0;
	int q = 0;
		for (;i <= n-1;i++)
		{
			for (int j = 0;j <= 2;j++)
			{
				if (abs(a[i][j] - a[i + 1][j]) <= 5)
				{
					count++;
				}
				if (count == 3)
				{
					if((a[i][0]+a[i][1]+a[i][2])-(a[i+1][0]+a[i+1][1]+a[i+1][2])<=10)
					count1++;
					count = 0;
				}
			}
			if (i == n - 1)
			{
				i = q;
				q++;
			}
		}
	printf("%d", count1);
}

求助，本人太菜。。。。。。