ERROR "Control can not leave body of finally clause"

Question

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace test2

{

public class a

{

public int m1()

{

try

{

return 10;

}

catch (Exception e)

{

return 20;

}

finally

{

return 30;

}

}

}

class Program

{

public static void Main(string[] args)

{

a A = new a();

int i = A.m1();

// S.O.P(i);

Console.WriteLine("" + i);

Console.ReadLine();

}

}

}