#include<iostream>
#include<cstring>
using namespace std;
int v;
int n=1;
int count=1;
int main(){
		cin>>v;
		v=v-1;
		while(v>=count*2){
			n++;
			count*=2;
			v-=count;
		}
		if(v==0){
		cout<<n<<endl;
	}
	else cout<<n+1<<endl;
	return 0;
}