Exercise:

1. Soak red beans, coix seed and lily in water for 2 hours respectively (easy to cook).

2. Peel the yam and cut it into small pieces, and soak it in water for a while (put a little salt in the water to prevent oxidation).

3. Put red beans, coix seed and lily into the pot and add water to boil for about 40 minutes.

4. Pour in yam and cook for about 20 minutes.

5. Finally, add rock sugar until it melts.