Solution: Big O of a Nested Loop with Addition

int n = 10; // 'n' can be anything, this is just an example
int sum = 0;
double pie = 3.14;
for (int var = 1; var < n; var += 3)
{
    System.Console.WriteLine(pie);
    for (int j = 1; j < n; j += 2)
    {
        sum += 1;
        System.Console.WriteLine(sum);
    }
}