Operations with Numbers

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Operations_with_Numbers
{
    class Program
    {
        static void Main(string[] args)
        {
            var n1 = int.Parse(Console.ReadLine()); // 0...40 000
            var n2 = int.Parse(Console.ReadLine()); // 0...40 000
            var operatoor = Console.ReadLine(); // + , -, *, /, %

            double result = 0;
            string parity = "odd";

            if ((operatoor == "+") || (operatoor == "-") || (operatoor == "*"))
            {
                if (operatoor == "+")
                {
                    result = n1 + n2;
                    if ((result % 2 == 0)) parity = "even";
                }
                if (operatoor == "-")
                {
                    result = n1 - n2;
                    if ((result % 2 == 0)) parity = "even";
                }
                if (operatoor == "*")
                {
                    result = n1 * n2;
                    if ((result % 2 == 0)) parity = "even";
                }
                Console.WriteLine($"{n1} {operatoor} {n2} = {result} – {parity}");
            }

            if (n2 == 0)
            {
                Console.WriteLine($"Cannot divide {n1} by zero");
                Environment.Exit(0);
            }
            if (operatoor == "/")
            {
                result = 1.0 * n1 / n2;
                Console.WriteLine($"{n1} / {n2} = {result:f2}");
            }
            if (operatoor == "%")
            {
                result = n1 % n2;
                Console.WriteLine($"{n1} % {n2} = {result}");
            }
        }
    }
}