#include <stdio.h>   // for printf, scanf

double compute_result(int A)
{
  double a2 = (double) A;
  double result = (a2 - 0.5) * a2 * (a2 + 0.5);

  return result;
}


int main()
{
  int a;
  printf("please enter an integer A:\n");
  scanf("%d", &a);

  double result = compute_result(a);
  printf("the result is %lf\n", result);
}