#include <iostream>
using namespace std;

int main() {
    int d, ans;
    cin >> d;
    if(d < 4)
        ans = 0;
    else {
        int x = (d - 4) /2;
        if(x % 2)
            ans = (x/2 + 2) * (x/2 + 1);
        else
            ans = (x/2 + 1) * (x/2 + 1);
    }
    cout << ans << endl;
}