#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef string str;
int main()
{
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	ll n, countt = 0;
	cin >> n;
	while (n > 1)
	{
    	n = (n + 1) / 2; 
	    countt++;
	}
	cout << countt;
	return 0;
}