using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        List<string> li = new List<string>();

            li.Add("Output-PROD-EUR-VI-VI1PR08OC0020-20180410_20_26_09-hadoop.log.txt");

            li.Add("Output-PROD-EUR-VI-VI1PR08OC0020-20180410_20_06_09-CodePackage-MoonWorkflow-Expansion.txt");

            li.Add("Output-PROD-EUR-VI-VI1PR08OC0020-20180410_20_03_17_AuthenticateHiveUserWithKdcRuntime_attempt1.txt");

            li.Add("Errors-PROD-EUR-VI-VI1PR08OC0020-20180410_20_24_23_TerminateRunningYarnApplicationsRuntime.txt");

        for (int i =0 ; i< li.Count() ; i++ )

{

            string keyy = li[i]; 

   Match match = Regex.Match(keyy, @"\d{8}_\d{2}_\d{2}_\d{2}");

        string date = match.Value;

            li[i] =  keyy.Split('-')[0] +"-"+ date + keyy.Replace(keyy.Split('-')[0],"").Replace("-"+date,"");

            Console.WriteLine(li[i]);

}

    }

}