Determine positions of the longest and shortest word inside of a string list

List<string> words = new List<string>();
string input;

do
{
    Console.Write("Woord? ");
    input = Console.ReadLine();
    words.Add(input);

} while (!string.IsNullOrWhiteSpace(input));

string longWord = words[0];
string shortWord = words[0];

foreach (string word in words)
{
    if (word.Length < shortWord.Length)
    {
        shortWord = word;
    }
    else if (word.Length > longWord.Length)
    {
        longWord = word;
    }
}

int indexShortWord = words.IndexOf(shortWord);
int indexLongWord = words.IndexOf(longWord);
int addingUp = indexShortWord + indexLongWord;

Console.WriteLine($"Het langste woord is {longWord}");
Console.WriteLine($"Het kortste woord is {shortWord}");
Console.WriteLine($"De som van de posities is {addingUp}");

Console.ReadLine();