#include<iostream>
using namespace std;
int shulie(int n)
{
    if(n==1)return 0;
    int x,m=0;
    if(n%2==0)x=n/2;
    else x=n/2+1;
    for(int i=1;i<=x;i++)
    {
        m++;
    }
    return m+shulie(m);
};
int main()
{
    int n;
    cin>>n;
    cout<<shulie(n)<<endl;
    return 0;
}