/*
	http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0009
	Prime Number
*/

#include <stdio.h>
int main(void)
{
	int n, i, j, p=0;
	while(scanf("%d",n)!=EOF){
		for (i = 1; i <= n; ++i)
		{
			for (j = 2; j < i; ++j)
			{
				if (i % j == 0)
				{
					++p;
					break;
				}

			}
		}
	}

	printf("%d\n", p);
	return 0;
}