How to implement bubblesort inside main function

Question

Hi I make function to bubble sort but i need to implement it inside

Main function as following :

 class Program
    {
        static void Main(string[] args)
{
}
}

How to implement bubblesort function inside Main function 

 and recieve number to implement it ?

public List<int> bubblesort(List<int> a)
{
int temp;
// foreach(int i in a)
for(int i=1; i<=a.Count; i++)
for(int j=0; j<a.Count-i; j++)
if (a[j] > a[j + 1])
{
temp = a[j];
a[j] = a[j + 1];
a[j + 1] = temp;
}
return a;
}