10c.py

from math import sqrt

# Set up the array
m = 2000000
nums = range(m)
nums[1] = 0

i = 0
while i**2 < m:
    if nums[i] == 0:
        i += 1
        continue
    # The next non-zero should be prime
    p = nums[i]

    # Zero out all the multiples of p, starting at the square (optimization)
    j = p
    while j * p < m:
        nums[j * p] = 0
        j += 1

    i += 1

t = 0
for p in nums:
    t += p
print t