#include <iostream>
#define N 10000000

using namespace std;



int main()
{
	long prime[N];
	long counter = 0;
	for (long i = 2; i < N; i++)
	{
		prime[i] = 1;
	}
	prime[0] = 0;
	prime[1] = 0;

	for (long i = 2; i < (N); i++)
	{
		if (prime[i] == 1)
		{
			for (long j = 2; j*i < N; j++)
			{
				prime[i*j] = 0;
			}
			counter += 1;
		}
	}
	cout << "the counter is:"<<counter << endl;

    return 0;
}