#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  cin >> n;
  long long i = 1, c = 0, s = 1;
  while (1) {
    if (s >= n) break;
    c++;
    i *= 2;
    s += i;
  }
  cout << c + 1;
}
