using System;

class IntSequenceClient{

  public static void Main(){
    IntSequence is1 = new IntSequence(-5, -1, 7, -8, 13),
                is2 = new IntSequence();

    ReportMinMax(is1);
    ReportMinMax(is2);     
  }

  public static void ReportMinMax(IntSequence iseq){
    if (iseq.Min().HasValue && iseq.Max().HasValue)
      Console.WriteLine("Min: {0}. Max: {1}", 
                         iseq.Min(), iseq.Max());
    else
      Console.WriteLine("Int sequence is empty");
  }

}