Incorrect Format?

I have this code, it reads in a text file and stores it in a string[] called 'sh2VolumeData', it contains lots of numbers. So to cater for the integers I have tried to convert the string[] to a int[] so that my bubblesort can sort them. However, when I try to run my code I get the same error message saying that the input is in the incorrect format.

Any ideas why? Thanks.

The error occurs when I input "volume" into the cmd to go to the else if statement.

PLEASE NOTE - SOME OF MY CODE COMMENTS ARE NOT CORRECT.

else if(input2.ToLower() == "volume") //If the user types 'day', they will be directed here. They can then choose between the unsorted array or the sorted array.
{
    int[] intSh2VolumeData = new int[sh2VolumeData.Length];

    for (int x = 0; x < sh2VolumeData.Length; x++)
    {
        intSh2VolumeData[x] = Convert.ToInt32(sh2VolumeData[x]);
    }

    Console.Write("To view this Array unsorted, input 'un', to see this Array sorted input 's'.");
    string input3 = Console.ReadLine();

    if(input3.ToLower() == "un")
    {
        Console.WriteLine("\n");
        Console.WriteLine("UNSORTED");

        for (int i = 0; i < intSh2VolumeData.Length; i++)
            Console.Write(intSh2VolumeData[i] + "\n");
    }

    else if(input3.ToLower() == "s")
    {
        int temp = 0; 
        for (int write = 0; write < intSh2VolumeData.Length; write++) 
        {
            for (int sort = 0; sort < intSh2VolumeData.Length - 1; sort++) 
            {
                if (intSh2VolumeData[sort] > intSh2VolumeData[sort + 1]) 
                {
                    temp = intSh2VolumeData[sort + 1];
                    intSh2VolumeData[sort + 1] = intSh2VolumeData[sort];
                    intSh2VolumeData[sort] = temp;
                }
            }
        }
            Console.WriteLine("\n\n\nSORTED");

        for (int i = 0; i < intSh2VolumeData.Length; i++)
            Console.Write(intSh2VolumeData[i] + "\n");

            Console.WriteLine("\nMax Value"); //144
            Console.WriteLine(intSh2VolumeData[143]);
            Console.WriteLine("\nMin Value"); //1
            Console.WriteLine(intSh2VolumeData[0]);

    }

    else if(input3.ToLower() != "a" || input3.ToLower() != "d")
    {
        Console.WriteLine("\nSorry, Please enter 'un' or 's' next time.");
    }
}