using System;
using System.Linq;
using System.Collections.Generic;
using System.Data;
using System.Text;

namespace NumSequenceCalculator
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("This app calculates a sequence of numbers from 1 to n. n must NOT be bigger" +
                " than 9. The app works until the command END.");

            Console.Write("Enter a formula with argument n. For example: a=n+1 ");
            var inputFormula = Console.ReadLine().Split('=');
            Console.Write("Calculate for n= ");
            int k = int.Parse(Console.ReadLine());
            char counter = '1';

            while (inputFormula[1] != "END")
            {


                while (int.Parse(counter.ToString()) != k+1)
                {
                    List<char> charList = inputFormula[1].ToList();
                    for (int i = 0; i < charList.Count; i++)
                    {
                        if (charList[i] == 'n')
                        {
                            charList[i] = counter;
                        }
                        //!
                    }
                    counter++;

                    var foo = new string(charList.ToArray());
                    var sb = new StringBuilder();
                    var dt = new DataTable();
                    sb.Append(foo).Append(" = ").Append(dt.Compute(foo, ""));


                    Console.WriteLine(sb.ToString());
                }

                inputFormula = Console.ReadLine().Split('=');
                k = int.Parse(Console.ReadLine());
            }

        }
    }
}