This problem begins with two single-digit numbers. The next number is obtained by adding the first two numbers together and saving only the ones-column-digit.This process is repeated until the “necklace” closes by returning to the original two numbers. For example, if the starting numbers are 1 and 8, twelve steps are required to close the “necklace”:
1 8 9 7 6 3 9 2 1 3 4 7 1 8
I need a program that will ask for the user two input 2 numbers ( firstNumber and secondNumber)
Then the program will show the number of steps until the last 2 numbers are the same.
For example:

Enter the first number: 1
Enter the second number: 8
1 8 9 7 6 3 9 2 1 3 4 7 1 8
Your number required 12 steps.

This is what I have created...


static void Main(string[] args)
{
double firstNumber;
double secondNumber;
double variableAnswerOne;
double variableAnswerTwo;

Console.Write("Enter the first number:");
firstNumber = double.Parse(Console.ReadLine());

Console.Write("\nEnter the second number:");
secondNumber = double.Parse(Console.ReadLine());

Console.WriteLine(firstNumber + secondNumber);
variableAnswerOne = firstNumber + secondNumber;
Console.WriteLine(secondNumber + variableAnswerOne);
variableAnswerTwo = secondNumber + variableAnswerOne;

do
{
variableAnswerOne = variableAnswerTwo + variableAnswerOne;
Console.WriteLine(variableAnswerOne + variableAnswerTwo);
variableAnswerTwo = variableAnswerOne + variableAnswerTwo;
Console.WriteLine(variableAnswerTwo + variableAnswerOne);
}
while (variableAnswerOne != firstNumber && variableAnswerTwo != secondNumber);


Console.ReadKey(true);

}
}
}

Im not sure if it works at the start, but I do know that it doesnt work completely because it goes into an "infinity" loop.

HELP PLEASE