Minimum Cost - HackerRank woman codesprint #2 - using LINQ only, timeout on test case 11 - 15

MinimumCost_usingLINQ1.cs

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

namespace minimumLoss
{
    class Program
    {
        static void Main(string[] args)
        {
            Process();           
        }

        private static void Process()
        {
            int n = int.Parse(Console.ReadLine());

            Int64[] prices = new Int64[n];

            string[] arr = Console.ReadLine().Split(' ');
            prices = Array.ConvertAll(arr, Int64.Parse);

            Console.WriteLine(MinimumLossCal(n, prices));
        }

        /*
         * Try this one - Nov. 30, 2016
         * 
         * source code from:
         * http://codereview.stackexchange.com/a/148557/123986
         */
        private static Int64 MinimumLossCal(int n, Int64[] prices)
        {
            return prices
                //calculate all the differences
                 .SelectMany((currentPrice, i) => prices.Take(i).Select(p => p - currentPrice))
                //pick only those, that are positive (loss)
                 .Where(difference => difference > 0)
                //pick minimum
                 .Min();
        }       
    }
}