#include <bits/stdc++.h>
using namespace std;

int main()
{
	int n;
	int a[100000] = {0};
	int b[100000] = {0};
	int cnt = 1;
	int allx, ally;

	cin >> n;
	for(int i = 0; i < n; i++)
	{
		cin >> a[i] >> b[i];
	}
	allx = a[0];
	ally = b[0];
	for(int j = 1; j < n; j++)
	{
		if(abs(allx -a[j]) <= 10 || abs(ally -b[j]) <= 10)
		{
			continue;
		}
		else
		{
			allx = a[j];
			ally = b[j];
			cnt++;
		}
	}
	printf("%d\n", cnt);
	return 0;
}