using System;           

public class Program

{

    public static void Main()

    {

        Console.WriteLine("By Brandon Eduardo Cortes Correa");

        Console.WriteLine("");

            int n, i, flg1=1,flg2=1,flg3=0,j;

    Console.Write("\n\n");

    Console.Write("Check whether a number can be express as sum of two prime numbers:\n");

    Console.Write("-------------------------------------------------------------------");

    Console.Write("\n\n");  

    Console.Write("Input  a positive integer: ");

    n = Convert.ToInt32(Console.ReadLine());    

   for(i=3; i<=n/2; i++)

     {     

/*---------- check for prime---------------*/

      flg1=1;

      flg2=1;

      for(j=2; j<i; j++)

       {     

         if(i%j==0)

           { flg1=0;j=i;}

        }

      for(j=2; j<n-i; j++)

       {     

         if((n-i)%j==0)

           { flg2=0;j=n-i;}

        }

         if(flg1==1 && flg2==1)

           { Console.Write("{0} =  {1} + {2}  \n",n,i,n-i); 

           flg3=1;}

    }

         if(flg3==0)

           {Console.Write("\n{0} can not be expressed as sum of two prime numbers.\n\n",n);}    

}

}