using System;

public abstract class IntSequence {
  public abstract int Min {get;}
  public abstract int Max {get;}
  public abstract int Sum();
}    

public class IntInterval: IntSequence{

  private int from, to;

  public IntInterval(int from, int to){
    this.from = from;
    this.to = to;
  }

  public int From{
    get{return from;}
  }

  public int To{
    get{return to;}
  }

  public override int Min{
    get {return Math.Min(from,to);}
  }

  public override int Max{
    get {return Math.Max(from,to);}
  }
    
  public override int Sum(){
    int res = 0;
    int lower = Math.Min(from,to),
        upper = Math.Max(from,to);

    for (int i = lower; i <= upper; i++) 
       res += i;
    return res;
  }
}     

public class IntSingular: IntSequence{

  private int it;

  public IntSingular(int it){
    this.it = it;
  }

  public int TheInt{
     get{return it;}
  }

  public override int Min{
    get {return it;}
  }

  public override int Max{
    get {return it;}
  }

  public override int Sum(){
    return it;
  }
}     


public class IntCompSeq: IntSequence{

  private IntSequence s1, s2;  // Binary sequence: Exactly two subsequences.

  public IntCompSeq(IntSequence s1, IntSequence s2) {
    this.s1 = s1;
    this.s2 = s2;
  }

  public IntSequence First{
    get{return s1;}
  }

  public IntSequence Second{
    get{return s2;}
  }

  public override int Min{
    get {return Math.Min(s1.Min, s2.Min);}
  }

  public override int Max{
    get {return Math.Max(s1.Max, s2.Max);}
  }

  public override int Sum(){
    return s1.Sum() + s2.Sum();
  }
}