Solution: Big O of a Nested Loop with Subtraction

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