#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
 
using namespace std;
 
#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(int i=(a);i<(b);++i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
 
#define MOD 1000000009
 
int main(){
  int d;
  cin>>d;
  if(d<4){
    cout << 0 << endl;
    return 0;
  }
  d -= d%2;
  if(d%4==0){
    cout << (d/4)*(d/4) << endl;
    return 0;
  }
  cout << (d/4)*(d/4+1) << endl;
  return 0;
}