#include <iostream>

typedef unsigned int uint;

int main() {
	int n;
	std::cin >> n;
	if (n<=1) {
		std::cout << 0 << std::endl;
		return 0;
	}

	int num_bis = 1;
	int i;
	for (i=1; i<n; ++i) {
		num_bis *= 2;
		if (num_bis >= n)
			break;
	}

	std::cout << i << std::endl;
	return 0;
}