Books like Elements of Discrete Mathematics
C. L. Liu
Elements of Discrete Mathematics is 433 pages, about 7 hours 56 minutes at 250 words a minute.
7 books to read next
How long each takes
Schaum's Outline of Theory and Problems of Discrete Mathematics 9.2 h 
A First Course in Abstract Algebra 9.5 h 
Discrete and Combinatorial Mathematics 15.3 h 
Introductory Combinatorics 11.4 h A Book of Abstract Algebra 7.0 h 
Modern Algebra 6.4 h 
Applied Abstract Algebra 9.6 h Bar height shows length. Estimated at 250 words a minute.