import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws FileNotFoundException {
		long t = System.currentTimeMillis();
		new Main().run();
		System.err.println(System.currentTimeMillis() - t);
	}

	public void run() {
		Scanner sc = new Scanner(System.in);
		double n = sc.nextDouble();
		n = Math.sqrt(n / Math.PI);
		long ans = (long) n;
		while(ans<1)++ans;
		System.out.println(ans);
	}

	static void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}

}