gistfile1.cs

void Main()
{
	var list = new List<int> { 1, 2, 3, 4, 5, 6 };
	
	var sumOfAllItems = list.Sum(_ => Print(_));
	
	Console.WriteLine(sumOfAllItems);
}

static int Print<T>(T item)
{
	var s = item.ToString();
	
	Console.WriteLine(s);
	
	return s.Length;
}