#include <bits/stdc++.h>
using namespace std;
inline void IO() {
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
}
int main(int argc, char const *argv[]) {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int n;
  cin >> n;
  long long int lb = 1, inc = 0, ub = 1;
  while (true) {
    if (n >= lb && n <= ub) break;
    lb = ub + 1;
    inc += 1;
    ub = lb + pow(2, inc) - 1;
  }
  cout << inc + 1;
  return 0;
}
