I've finally managed to get the ACCEPTED message and i'm quite satisfied with that... had to change 2-3 conceipt ideas... At the end may be not the best i could write but please tell me what do you think about the source:


#include <stdio.h>
int main(void)
{
 unsigned long int aa;
 scanf("%ld",&aa);
 int dvoiki=0,troiki=0,petici=0,sedmici=0,chetvorki=0,devetki=0,shestici=0,osmici=0;
 switch(aa){
            case 0:
                 printf("10");
                 break;
            case 1:
                 printf("1");
                 break;
            default:
              for (int j=2;j<=9;j++)if(aa%j==0)
                      {switch (j){
                               case 2:
                                    dvoiki++;
                                    break;
                               case 3:
                                    troiki++;
                                    break;
                               case 5:
                                    petici++;
                                    break;
                               case 7:
                                    sedmici++;
                                    break;
                                    }
                      aa=aa/j--;
                      }
          osmici=dvoiki/3;
          dvoiki=dvoiki%3;
           devetki=troiki/2;
            troiki=troiki%2;
          if ((dvoiki>1)&&(troiki>0)) {dvoiki--;troiki--;shestici++;}
          if ((dvoiki>0)&&(troiki>2)) {dvoiki--;troiki--;shestici++;}
          if ((dvoiki>0)&&(troiki>0)) {dvoiki--;troiki--;shestici++;}

          chetvorki=dvoiki/2;
          dvoiki=dvoiki%2;

          if (aa>7) printf("-1");
          else{
          for(int i=1;i<=dvoiki;i++)printf("2");
          for(int i=1;i<=troiki;i++)printf("3");
          for(int i=1;i<=chetvorki;i++)printf("4");
          for(int i=1;i<=petici;i++)printf("5");
          for(int i=1;i<=shestici;i++)printf("6");
          for(int i=1;i<=sedmici;i++)printf("7");
          for(int i=1;i<=osmici;i++)printf("8");
          for(int i=1;i<=devetki;i++)printf("9");
          }
}
return 0;
}

I think C# RULIT
using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1014
{
    class Program
    {
        static void Main(string[] args)
        {
            string result = "";
            int num = int.Parse(Console.ReadLine());
            if (num == 1)
                Console.WriteLine("1");
            else
            {
                if (num == 0)
                    Console.WriteLine("10");
                else
                {
                    int[] digitArr = new int[10];
                    for (int i = 9; i > 1; i--)
                    {
                        while (num % i == 0)
                        {
                            digitArr[i]++;
                            num /= i;
                        }
                    }
                    if (num != 1)
                        Console.WriteLine("-1");
                    else
                    {
                        for (int i = 2; i < 10; i++)
                        {
                            for (int j = 0; j < digitArr[i]; j++)
                                result += i.ToString();
                        }
                        Console.WriteLine(result);
                    }
                }
            }
        }
    }
}