class Cons{
  int x1;
  Object x2;
  Cons( int x1, Object x2){
    this.x1 = x1;
    this.x2=x2;
  }
  public String toString(){
    StringBuffer result = new StringBuffer();
    result.append("Cons")
    .append("(")
    .append(x1)
    .append(",")
    .append(x2)
      .append(")");
    return result.toString();
  }
}