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

public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		int num = Integer.parseInt(br.readLine());
		int count = 0;
		int base = 1;

		while (num > base) {
			base *= 2;
			count++;
		}
		System.out.println(count);

	}
}