limit = 2000000

number_list = [False] + [True]*(limit-1)
list_len = len(number_list)

def next_prime(i):
	global number_list
	global list_len
	x = i+1
	while(x <= list_len):
		if number_list[x-1] == True:
			break
		x += 1
	return x

i = 2

while(i*i <= list_len):
	x = i*i
	while(x <= list_len):
		number_list[x-1] = False
		x += i
	i = next_prime(i)


sum = 0

for i in xrange(1, limit+1):
	if number_list[i-1]:
		sum += i

print sum