static void Main(string[] args)
{
long sum = 2 + 5;
long sum1 = 0;
long sum3 = 0;
long sum7 = 0;
long sum9 = 0;
long limit = 2000000;
PrimeNumber pn = new PrimeNumber();
for (long i = 1; i < limit; i++)
{
if (pn.isPrime(i))
sum1 += i;
i += 9;
}
for (long i = 3; i < limit; i++)
{
if (pn.isPrime(i))
sum3 += i;
i += 9;
}
for (long i = 7; i < limit; i++)
{
if (pn.isPrime(i))
sum += i;
i += 9;
}
for (long i = 9; i < limit; i++)
{
if (pn.isPrime(i))
sum9 += i;
i += 9;
}
sum += sum1 + sum3 + sum7 + sum9;
Console.WriteLine("Sum: {0}", sum);
Console.ReadKey();
}