main = interact $ unlines . map (show . sum_of_prime_numbers . read) . (takeWhile (/="0")) . lines

sum_of_prime_numbers n = sum (take n primes)

primes = 2:3:[x | i<-[1..], j<-[-1,1], let x = 6*i+j, isPrime x]
 where isPrime n = null [i | i<-takeWhile (\x -> x*x <= n) primes, rem n i == 0]