Does anyone have any suggestions for an online or physical book for self teaching Discrete Mathematics.

Hi All,

I am interested in pursuing a masters in CS in the next few years. I have several years of experience working at a software company and an engineering undergrad. One recommended requirement that i typically see grad schools looking for from non CS undergrads is a background in Discrete Mathematics. Does anyone have a recommendation for a online or printed book to self learn Discrete Mathematics? Emphasis on the "self learn" since i won't have resources such as other students or professors.