#include <iostream>
#include <sstream>
#include <vector>
#include <algorithm>
#include <string>
#include <functional>
#include <numeric>
#include <ctype.h>
#include <cstdlib>
#include <string.h>
#include <cmath>
#include <cstdio>





using namespace std;

bool isPrime(int num);

int main()
{
	int count = 0;
	/*int m = 2, n = 0, num;

	cin >> num;

	int *data = new int[num + 1];
	int *result = new int[num + 1];

	data[0] = 0;
	data[1] = 0;

	do
	{
		for (i = 2 * m; i < num + 1; i += m)
		{

		}
	}
	while
	{

	}*/
	const int N = 1000;
	std::vector<bool> isPrime(N + 1, true);    // ?´???°????????°?????¨??¨ON???
	for (int i = 2; i < N; ++i) {
		if (isPrime[i])
		{   
			count++;

			for (int k = i + i; k <= N; k += i)
				isPrime[k] = false;      // ?´???°????????°????´???°????????°?????¨???OFF???
		}
	}
	return 0;






	
}