from math import*
from threading import*

def input_steps():
    try:
        n=int(input("Calculer les nombres premiers de 1 a:"))
        if n<=2:
            n=3
        return n
    except:
        return input_steps()

def is_not_prime(a,liste):
	nb_div=1
	if (a-1)%6==0 or (a+1)%6==0:
		nb_div=0
		for nb in liste:
			if nb<=sqrt(a):
				nb_test=a
				while (nb_test%nb)==0:
					nb_div+=1
					nb_test=(nb_test//nb)

			else:
				break

	return nb_div

def get_numbers(fin):
	k=3
	liste=[2,3,5]
	while k<fin:
		k+=4
		th1=Thread(target=is_not_prime(k,liste))
		th2=Thread(target=is_not_prime(k+2,liste))
		test_k1=th1.start()
		test_k2=th2.start()

		th1.join()
		th2.join()
		if test_k1==0:
			print(k)
			liste.append(k)
		if test_k2==0:
			print(k+2)
			liste.append(k+2)

	return liste

limit=input_steps()

print("Nombres premiers jusqu'a {}:".format(limit))
print("2\n3\n5")
numbers=get_numbers(limit)

index_n=numbers.index(numbers[-1])
print(">>>{} Valeurs trouvées".format(index_n+1))