#include <bits/stdc++.h>
using namespace std;
const int MOD = (int)1e9 + 7;
const double EPS = 1e-9;
const int INF = INT_MAX;
const long long INFLL = (long long)1e18;
const double PI = acos(-1.0);
template <class T>
T gcd(T a, T b) {
  return b ? gcd(b, a % b) : a;
}
template <class T>
T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}
const int N = (int)2e5 + 5;
const int P = 1 << 18;
long long n;
int main() {
  ios::sync_with_stdio(false);
  cout.setf(ios::fixed | ios::showpoint);
  cout.precision(8);
  cin >> n;
  long long sum = 1ll;
  long long cnt = 1ll;
  if (n == 1ll) return !printf("1\n");
  for (long long i = 2;; i *= 2) {
    sum += i;
    cnt++;
    if (sum >= n) return !printf("%I64d\n", cnt);
  }
  return 0;
}
