#include <iostream>
#include <vector>
#include <algorithm>
#define REP(i,n) for(int i=0;i<(n);++i)
#define SORT(a) sort((a).begin(),(a).end())
#define PB push_back
using namespace std;
typedef vector<int> VI;

int main(){
  int N;
  cin >> N;
  --N;
  int r = 0;
  while(N != 0){
    ++r;
    N >>= 1;
  }
  cout << r << endl;
}