trait MyOperations {
  fn my_div(self, den: i64) -> Option<i64>;
}

impl MyOperations for i64 {
  fn my_div(self, den: i64) -> Option<i64>
  {
    if den != 0 {
      Some(self / den)
    } else {
      None
    }
  }
}

fn my_sum(a: &Option<i64>, b:&Option<i64>) -> Option<i64>
{
  if let Some(va) = a {
    if let Some(vb) = b {
      Some(va + vb)
    } else {
      None
    }
  } else {
    None
  }
}


fn main()
{
  let a = 6.my_div(3);
  let b = 8.my_div(2);
  let c = 6.my_div(0);
  let r1 = my_sum(&a, &b);
  let r2 = my_sum(&a, &c);

  if let Some(v) = r1 { 
    println!("6 / 3 + 8 / 2 = {}", v);
  } else {
    println!("6 / 3 + 8 / 2 = None");
  }
  if let Some(v) = r2 { 
    println!("6 / 3 + 6 / 0 = {}", v);
  } else {
    println!("6 / 3 + 6 / 0 = None");
  }
}