import java.util.Scanner; // codeUp, 2625, 삼각화단 public class Main { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n = sc.nextInt(); int cnt = 0; for (int i = 1; i < n; i++) { for (int j = 1; j <= i; j++) { for (int k = 1; k <= j; k++) { if (n == i + j + k) { if (i < j + k) { cnt++; } } } } } System.out.println(cnt); } }