using System;

using System.Globalization;

using System.Text.RegularExpressions;

​

class Program

{

    static void Main()

    {

        string[] inputs = { "6 months", "3months", "1 year", "2 years", "1 month" };

​

        foreach (string input in inputs)

        {

            TimeSpan timeSpan = ParseToTimeSpan(input);

            Console.WriteLine($"Input: {input}, TimeSpan: {timeSpan}");

        }

    }

​

    public static TimeSpan ParseToTimeSpan(string input)

    {

        // Regular expression to match the input string format

        Regex regex = new Regex(@"(\d+)\s*([a-zA-Z]+)");

        Match match = regex.Match(input);

​

        if (!match.Success)

        {

            throw new ArgumentException("Invalid input format.");

        }

​

        // Extract the value and unit from the input string

        int value = int.Parse(match.Groups[1].Value);

        string unit = match.Groups[2].Value.ToLower(CultureInfo.InvariantCulture);

​

        // Calculate the equivalent TimeSpan based on the unit

        switch (unit)

        {

            case "month":

            case "months":

                return TimeSpan.FromDays(value * 30.44);

            case "year":

            case "years":

                return TimeSpan.FromDays(value * 365.25);

            default:

                throw new ArgumentException("Invalid time unit.");

        }

    }

}

​