Buddhism.

There is none!

atheistic

Most Czech's are atheistic. It is the most atheistic country in the world, with over 60% of the population declaring no religious affiliation.

To my knowledge atheism is not philosophocal, therefore existentialism, which means existence, is moot. We do believe that humans, religious or non, have problems. I don't really assume they exist, but research through independant studies conclude humans have problems, minor and major.