How to use a variable that could potentially be null in C#? [closed]

I have this C# code. It works well, but it has these warnings on the Console.WriteLine (green irregular lines below). After checking, it says

Nullable Warnings: you are using a variable that could potentially be null, but you haven't checked for that possibility (e.g., using Console.ReadLine() without checking for null)

This is the code:

static void Main(string[] args) { Console.WriteLine("Enter a number"); String text1 = Console.ReadLine(); int.TryParse(text1, out int number1); Console.WriteLine("Enter a second number"); String text2 = Console.ReadLine(); int.TryParse(text2, out int number2); string count; int sum; sum = number1 + number2; Console.WriteLine("The sum of both numbers is "+ sum); Console.ReadLine(); }