#include <bits/stdc++.h>
using namespace std;
const int MAX = 100000;
int arr[55][55];
int main() {
  long long n;
  cin >> n;
  int i = 1;
  int res = 0;
  long long mx = 0;
  while (mx < n) {
    mx += i;
    i *= 2;
    res++;
  }
  cout << res;
  return 0;
}
