#include <algorithm>
#include <iostream>
#include <iomanip>
#include <climits>
#include <string>
#include <vector>
#include <cmath>
#include <set>
#include <map>
using namespace std;
using ll = long long;

int main(void)
{
  ll N, C = 0, B = 1;
  cin >> N;
  while (B < N)
  {
    C++;
    B *= 2;
  }
cout << C <<endl;
  return 0;
}