>>347
public abstract class Main {
 public static void main(String[] args) {
  Main main = new Sub();
  main.height = 1.70;
  main.weight = 70.0;
  System.out.printf("%.2f%n", main.calc());
 }

 double weight;
 double height;

 abstract double calc();
}

class Sub extends Main {
 @Override
 double calc() {
  return (double) weight / (height * height);
 }
}