Stacks and Queues - 2. Stack Sum

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

namespace Advanced
{
    class Program
    {
        static void Main(string[] args)
        {
            var line = Console.ReadLine().Split();

            var stack = new Stack<string>(line);

            while (true)
            {
                var input = Console.ReadLine().ToLower();

                if (input == "end")
                {
                    break;
                }

                var action = input.Split().ToArray();
                var command = action[0];

                if (command == "add")
                {
                    var firstNumber = action[1];
                    stack.Push(firstNumber);
                    var secondNumber = action[2];
                    stack.Push(secondNumber);
                }

                else if (command == "remove")
                {
                    var numbersToRemove = int.Parse(action[1]);

                    if (stack.Count >= numbersToRemove)
                    {
                        for (int i = 1; i <= numbersToRemove; i++)
                        {
                            stack.Pop();
                        }
                    }
                }
            }

            int sum = 0;

            foreach (var item in stack)
            {
                sum += int.Parse(item);
            }

            Console.WriteLine($"Sum: {sum}");
        }
    }
}