''' The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
Find the sum of all the primes below two million. '''

def makeP(x):
  P = [3]
  p = [3]
  n = 5
  while n < x:
    for i in p:
      if n % i == 0:
        break
    else:
      P.append(n)
    n += 2
    while p[-1] ** 2 < n:
      p.append(P[len(p)])
  return P


maxx = 2000000
maxxx = int(maxx ** 0.5)

prime = makeP(maxxx)

total = 2 + 3 + 5 + 7

for i in xrange(len(prime) - 1):
  for x in xrange(prime[i] ** 2 + 2, prime[i + 1] ** 2, 2):
    for p in prime[:i + 1]:
      if x % p == 0:
        break
    else:
      total += x

for x in xrange(prime[-1] ** 2 + 2, maxx, 2):
  for p in prime:
    if x % p == 0:
      break
  else:
    total += x

print total