def sieve_of_eratosthenes(n):
    nums = list(range(2, n))
    while nums:
        prime = nums[0]
        nums = [i for i in nums if i % prime]
        yield prime

def main():
    num = int(input("Primes up to: "))
    print()
    for i in sieve_of_eratosthenes(num):
        print(i, end=" ")
    print()


if __name__ == "__main__":
    main()