using System;

public class Program

{

    public static void Main()

    {

        int[,] input1={{0,2},{2,3},{2,2},{5,2}};

        int input2=Int32.Parse(Console.ReadLine());

        int time=input1[0,1];

        String se="c0-";

        int count=1;

        String le="";

        for(int i=1;i<input2;i++)

        {

           if(time<=input1[i,0])

              {

                time=time+input1[i,1];

                se=se+"c"+i+"-";

                count++;

              }

           else

             {

               le=le+"c"+i+"-";

             }

        }

      String ans="";

      if(count==input2)

       {

        ans="served";

       }

      else

      {

       se=se.Substring(0,se.Length-1);

       if(le.Length>0)

       le=le.Substring(0,le.Length-1);

       ans=se+":"+le;

       }

 Console.WriteLine(ans);

    }

}