#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;

int main() {
  int N; cin >> N;
  int ans = 0, now = 1;
  if(N == 1){
    cout << 0 << endl;
    return 0;
  }
  while(now < N){
    ans++;
    if(now*2 < N){
      now *= 2;
    }else{
      now = N;
    }
  }
  cout << ans << endl;
}