Return Height Of Heap Of Sand In Bottom Of Hourglass

I am working on program and have been struggling to get around step 5 and 6 given below.

I have got on with the first couple of points. Where to begin with steps 5 and 6.

Java Code:

class Hourglass {
int height;
int bottomHalf;
public Hourglass (int h) {
height =h;
}
public Hourglass (){
height=3;
}

/*Write a method dropGrain that simulates one grain of sand falling into the bottom half of the Hourglass. If all the sand is already at the bottom before a grain is dropped, this method should cause the hourglass to be flipped, meaning that all the sand will be in the top again. Then, one grain of sand should fall. */

//Hint: this method can be quite short. All you need to do is update one attribute.

public void dropGrain(){
}

/*Write a method getHeapHeight() which returns the height of the heap of sand in the bottom of the hourglass.

Hint: a triangle of height h contains h*h grains (=1+3+5+...+h).

So determining the height when the amount of sand in the bottom half is a square (1,4,9,16,...) is easy. Think about what happens if the amount of sand is not exactly a square.*/

public int getHeapHeight() {
} mh_sh_highlight_all('java');