#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n;
  cin >> n;
  int pp = 0, t = 0, i = 0;
  while (t < n) {
    t += pow(2, i);
    i++;
    pp++;
  }
  cout << pp;
}
