Please help me with the task: Diskspace calculator

Hello, I’m working on this task:

Your next task is to calculate the total amount of space that files occupy on a hard drive.
First, read an integer from the console that represents the total number of files. Then, read a series of numbers that represent the size of each file. Write a program that asks the user to input size of each of these files using the phrase: “Input size of {number} file:”. number represents the order of the files, starting with 1 and incrementing for each file. Finally, find the sum of all of the file sizes and output this result in the following format: “Total disk space is {sum} bytes.” For example:
Input size of 1 file:
Input size of 2 file:
Input size of 3 file:
Total disk space is 21 bytes.

Here is my code:

using System;

namespace ForLoops
   class DiskSpace
      static void Main(string[] args)
           Console.WriteLine("Input size of {number} file:");
           int numberOfFiles = int.Parse(Console.ReadLine());
           int totalSize = 0;

           for (int i = 1; i < numberOfFiles; i++)
               Console.WriteLine($"Input size of file {i}");
               int size = int.Parse(Console.ReadLine());

               totalSize += size;

           Console.WriteLine($"Total disk space is {totalSize} bytes:");

The ouput that the console gives me is:
“Input size of file 1
Input size of file 2
Total disk space is 9 bytes:”

And it gives me an error for:
" Errors from testing your code:

  • The code gave an unexpected output for input:


Can anyone please help me to solve it?