ArrayModifier

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

namespace ArrayModifier
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            List<int> numbers = Console.ReadLine().Split().Select(int.Parse).ToList();

            string command = string.Empty;

            while ((command = Console.ReadLine()) != "end")
            {
                string [] commandArray = command.Split();
                if (commandArray[0] == "swap")
                {
                    int index1 = int.Parse(commandArray[1]);
                    int index2 = int.Parse(commandArray[2]);
                    if(index1>=0 && index1<=numbers.Count-1 && index2 >= 0 && index2 <= numbers.Count - 1 && index1!=index2)
                    {
                        int firstElement = numbers[index1];
                        int secondElement = numbers[index2];
                        numbers[index1] = secondElement;
                        numbers[index2] = firstElement;
                    }
                }

                else if (commandArray[0] == "multiply")
                {
                    int index1 = int.Parse(commandArray[1]);
                    int index2 = int.Parse(commandArray[2]);
                    if (index1 >= 0 && index1 <= numbers.Count - 1 && index2 >= 0 && index2 <= numbers.Count - 1 && index1 != index2)
                    {
                        int firstElement = numbers[index1];
                        int secondElement = numbers[index2];
                        numbers[index1] = firstElement * secondElement;
                    }
                }

                else if (commandArray[0] == "decrease")
                {
                    for (int i = 0; i < numbers.Count; i++)
                    {
                        numbers[i] = numbers[i] - 1;
                    }
                }
            }

            Console.WriteLine(string.Join(", ",numbers));

        }

      }

    }