#include <bits/stdc++.h>

using namespace std;

int main()
{
  long long num, count = 0, bis = 1;
  cin >> num;

  if (num == 1)
  {
    cout << 0 << endl;
    exit(0);
  }

  while(1)
  {
    bis += bis;
    count++;

    if (num <= bis)
      break;
  }

  cout << count << endl;
}