#!/usr/bin/ruby

#PROBLEM:
#The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.

#Find the sum of all the primes below two million.


#SOLUTION

#Summing primes up to and with:
n=2*10**6

#Initializing. 2 is not recognized as prime using the method below and hence sum=2.

number=2
sum=2

while number < n+1 do
  k=1
  i=2

  while i < Math.sqrt(number)+1 and k == 1 do
    k=0 if number % i == 0 end
    i= i+1
  end
  sum = sum + k*number
  number = number+1
end

puts sum