import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		br.close();

		if (n == 1) {
			System.out.println(0);
			return;
		}

		List<Integer> sosuu = sosuuList(n);
		int ans = 1;
		for (int i = 1; i < sosuu.size(); i++) {
			int x = sosuu.get(i) + 2;
			Map<Integer, Integer> soinsu = bunkai(x);
			if (soinsu.size() == 1) {
				for (Integer o : soinsu.keySet()) {
					if (soinsu.get(o) == 2) {
						ans += 2;
					}
				}
			}
		}
		System.out.println(ans);
	}

	static List<Integer> sosuuList(int n) {
		List<Integer> sosuu = new ArrayList<Integer>();
		for (int i = 2; i <= n; i++) {
			int r = (int) Math.sqrt(i);
			boolean flg = false;
			for (Integer o : sosuu) {
				if (r < o) {
					break;
				}
				if (i % o == 0) {
					flg = true;
					break;
				}
			}
			if (!flg) {
				sosuu.add(i);
			}
		}
		return sosuu;
	}

	static Map<Integer, Integer> bunkai(int n) {
		Map<Integer, Integer> soinsu = new HashMap<Integer, Integer>();
		int end = (int) Math.sqrt(n);
		int d = 2;
		while (n > 1) {
			if (n % d == 0) {
				n /= d;
				if (soinsu.containsKey(d)) {
					soinsu.put(d, soinsu.get(d) + 1);
				} else {
					soinsu.put(d, 1);
				}
				end = (int) Math.sqrt(n);
			} else {
				if (d > end) {
					d = n - 1;
				}
				d++;
			}
		}
		return soinsu;
	}
}