Problem 10

问题描述：
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.

Find the sum of all the primes below two million.

	public static boolean IsPrime(long number) {
		int begin = 2;
		int end = (int) Math.sqrt(number) + 1;
		for (int i = begin; i < end; i++) {
			if (number % i == 0)
				return false;
		}
		return true;
	}

	public static long sum(){
		long result = 0;
		int begin = 2;
		int end = 2000000;
		for(int i=begin; i<end; i++){
			if(IsPrime(i)){
				result += i;
			}
		}
		return result;
	}