#include <bits/stdc++.h>
using namespace std;
int N;
int main() {
  cin >> N;
  int res = 0;
  if (1 <= N && N <= 100)
    for (int i = 0; N > 1; ++i) {
      N = N / 2;
      ++res;
    }
  cout << res << endl;
}
