#include <iostream>

using namespace std;

int main() {
	int N;
	int sum = 1, cnt = 0;

	cin >> N;
	if (N != 1) {
		while (1) {
			if (sum * 2 < N) {
				cnt++;
				sum *= 2;
			} else {
				break;
			}
		}
		cout << cnt + 1 << endl;
	}else{
		cout << 0 << endl;
	}

	return 0;
}