#include<iostream>
using namespace std;
int main(){
	float a,b=0;
	cin>>a;
	while(a>=0.5){
		a=a*1.0/2;
		b++;
	}cout<<b;
}
/**************************************************************
	Problem: 1062
	User: panyuchen
	Language: C++
	Result: Wrong Answer
****************************************************************/