// test.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
#include<fstream>
using namespace std;
int v[201];
int main()
{
	int n, i, j;
	int nr = 0;
	ifstream fin("ciur.in");
	ofstream fout("ciur.out");
	fin >> n;
	v[0] = 1;
	v[1] = 1;
	for (i = 2; i <= n; i++)
	{
		if (v[i] == 0)
			for (j = 2; j <= n / i; j++)
				v[i * j] = 1;
		if (v[i - 1] == 0)
			nr++;
	}
	if (v[n] == 0)
		nr++;
	fout << nr;
}