The second exercise book is used up today.

     Long time no updating... This night I am going to report something about my studying in discrete mathematics. After few days' work, I've completed the exercises in the first two sections of Chapter 1 of the book and I've made my step in Section 1.5. Many exercises I've done and many pages of the book I've read. To make it clear how many exercises I've done, I say that I've used up 2 exercise books, in both of which is full of my writing, my hard working.