task planner

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Threading;

namespace ConsoleApp1
{
    class Exam
    {
        static void Main(string[] args)
        {
            List<int> tasks = Console.ReadLine().Split().Select(int.Parse).ToList();

            string[] command = Console.ReadLine().Split().ToArray();

            while (command[0] != "End")
            {
                if (command[0] == "Complete")
                {
                    Completed(tasks, command);
                }
                if (command[0] == "Change")
                {
                    Change(tasks, command);
                }
                if (command[0] == "Drop")
                {
                    Drop(tasks, command);
                }
                if (command[1] == "Completed")
                {
                    Completed(tasks);
                }
                if (command[1] == "Incompleted")
                {
                    Incompleted(tasks);
                }
                if (command[1] == "Dropped")
                {
                    Dropped(tasks);
                }

                command = Console.ReadLine().Split().ToArray();
            }

            tasks.RemoveAll(x => x <= 0);

            Console.WriteLine(string.Join(" ", tasks));
        }

        private static void Completed(List<int> tasks, string[] command)
        {
            int index = int.Parse(command[1]);
            if (index >= 0 && index < tasks.Count)
            {
                tasks[index] = 0;
            }
        }

        private static void Change(List<int> tasks, string[] command)
        {
            int index = int.Parse(command[1]);
            int time = int.Parse(command[2]);
            if (index >= 0 && index < tasks.Count && (time >= 1 && time <= 5))
            {
                if (tasks[index] > 0)
                {
                    tasks[index] = time;
                }

            }
        }

        private static void Drop(List<int> tasks, string[] command)
        {
            int index = int.Parse(command[1]);
            if (index >= 0 && index < tasks.Count)
            {
                tasks[index] = -1;
            }
        }

        private static void Completed(List<int> tasks)
        {
            int count = 0;
            foreach (var item in tasks)
            {
                if (item == 0)
                {
                    count++;
                }
            }

            Console.WriteLine(count);
        }

        private static void Incompleted(List<int> tasks)
        {
            int count = 0;
            foreach (var item in tasks)
            {
                if (item > 0)
                {
                    count++;
                }
            }

            Console.WriteLine(count);
        }

        private static void Dropped(List<int> tasks)
        {
            int count = 0;
            foreach (var item in tasks)
            {
                if (item == -1)
                {
                    count++;
                }
            }

            Console.WriteLine(count);
        }
    }
}