#include<cstdio>
#include <iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> Pr;

int N;

int main()
{
	cin >> N;

	int cnt = 0,i=0;
	while (N > cnt) {
		i++;
		cnt = pow(2, i);
	}
	if (N == 1)i = 0;
	cout << i << endl;
	return	0;
}