using System;

public class Program

{

    public static void Main()

    {

        DateTime starttime,endtime;

        double difference;

        string[] timeFormats = new string[] { "yyyy-MM-dd HH:mm:ss", "M/d/yyyy H:m" };

        DateTime.TryParseExact("1/27/2014 3:00", timeFormats, null,System.Globalization.DateTimeStyles.None, out starttime);

        DateTime.TryParseExact("2014-01-27 04:50:00", timeFormats, null,System.Globalization.DateTimeStyles.None, out endtime);

        difference=(endtime-starttime).TotalMinutes;

        Console.WriteLine(difference);

    }

}

​