题目2

#include <iostream>
#include <string>
#include <math.h>
#include <stdio.h>
#include <time.h>
#include <algorithm>
using namespace std;

bool cmp(int a,int b)
{
	return a>b;
}
int main()
{
	


	int n;
	cin >>n;
	int num[65536]={0};
	for (int i = 1;i <=n;++i)
	{
		num[i] = -i;
	}
	for (int i = 1;i<=n;++i)
	{
		for (int j = 1;j<=n;++j)
		{
			if (num[j] % i==0)
			{
				num[j]=-num[j];
			}
		}
	}
	int count = 0;
	for (int i = 1;i <=n;++i)
	{
		if (num[i] > 0)
		{
			count++;
		}
	}
	cout << count <<endl;
	return 0;
}