#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,s;
    cin>>n;
	n%2!=0;
	s=(n+1)*((n+1)/4);
	cout<<s<<endl;
    return 0;
}
/**************************************************************
	Problem: 1003
	User: xiaojingxuan
	Language: C++
	Result: Wrong Answer
****************************************************************/