#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  int ans = 1;
  int x = 1;
  while (x * 2 <= n) {
    x *= 2;
    ans++;
  }
  cout << ans << "\n";
  return 0;
}
