import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Yukicoder47 {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String n = Integer.toBinaryString(Integer.parseInt(br.readLine()));
		int res = n.length() - 1;


		for (int i = 1; i < n.length(); i++) {
			if (n.charAt(i) == '1') {
				res++;
				break;
			}
		}

		System.out.println(res);
	}
}