#include <iostream>
#include <queue>
using namespace std;
int S=0;
int N;
queue <int> Q;
int main()
{
cin>>N;
Q.push(N);
while(!Q.empty())
{
int F = Q.front();
Q.pop();
if(F>1)
{
if(F%2==0)
{
S+=(F/2)*(F/2);
Q.push(F/2);
Q.push(F/2);
}
else
{
S+=(F/2)*(F/2+1);
Q.push(F/2);
Q.push(F/2+1);
}
}
}
cout<<S;
}