#include <iostream>
#include <vector>
using namespace std;

int knock4Bisket(int inPocket, int N)
{
    if (N == inPocket)
    {
        return 0;
    }
    else if (N >= inPocket * 2)
    {
        return 1 + knock4Bisket(inPocket * 2, N);
    }
    else
    {
        return knock4Bisket(inPocket - 1, N - 1);
    }
}

int main(void)
{
    int N;
    cin >> N;

    cout << knock4Bisket(1, N) << endl;

    return 0;
}