计算1+3！+5！+7！+9！之和（利用循环结构，和用S表示，结果用？输出）c#中的 谢谢帮忙

static void Main(string[] args)
{
Console.WriteLine(Process(9));

}
static int Process(int maxNum)
{
int s = 0;
int temp = 1;
for (int i = 1; i <= maxNum; i = i + 2)
{
temp = 1;
for (int j = 1; j <= i; j++)
{
temp *= j;
}
s += temp;
}
return s;
}
//测试通过！！~欢迎验收！~