import java.io.BufferedReader;
import java.io.InputStreamReader;

public class No080 {

    public static void main(String[] args) {
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(
                    System.in));
            int D = Integer.parseInt(br.readLine());
            int H = 0, W = 0;

            if (D > 4) {
                D = D - 4;
                H = 1;
                W = 1;
                int count = 0;
                while (D > 1) {
                    D = D - 2;
                    if (count % 2 == 0) {
                        H++;
                    } else {
                        W++;
                    }
                    count++;
                }
            }
            System.out.println(H * W);
        } catch (Exception e) {
            System.err.println("Error:" + e.getMessage());
        }
    }

}