#include<iostream>
#include<math.h>

int main(){
	int a;
	std::cin >> a;
	int ans = 0;
	int ni = 2;
	while (a > ni){
		ni *= 2;
		ans++;
	}
	if (a == 1)std::cout << 0 << std::endl;
	else if (a == 2)std::cout << 1 << std::endl;
	else std::cout << ans+1 << std::endl;
	return 0;
}