In C# How to correctly pass an int array to a function

how do I pass an array with an unknown number of integers to a function?
Can anybody tell me what I am doing wrong?

I get the following error when trying to run the code:

Error CS1501 No overload for method ‘Solution’ takes 6 arguments

using System;

namespace IntegerTest
{
    class Program
    {
        public static int Solution(int[] input)
        {
            Array.Sort(input);

            int index = 0;

            // Skip negatives
            while (index < input.Length && input[index] < 1)
                index++;

            int expected = 1;
            while (index < input.Length)
            {
                if (input[index] > expected)
                    return expected;

                // Skip number and all duplicates
                while (index < input.Length && input[index] == expected)
                    index++;

                expected++;
            }

            return expected;
        }

        public static void Main()
        {
            Console.WriteLine(Solution( 1, 3, 6, 4, 1, 2));

        }
    }

}
    

>Solution :

Your method accepts a int[], so create a new int[]

Solution(new int[] {1, 3, 6, 4, 1, 2});