interface ITask
{
    int TotalWork; // ProgressMax
    event Progresschanged; // Notifies of the current progress
    event ProgressComplete;
}

struct Task { int work, progress  }
class OverallProgress
{
    List<Task> tasks;
    int Work { get { return tasks.Sum(t=>t.work; } }
    int Progress { get { return tasks.Sum(t=>t.progress/t.work); } }
    void AddTask(Task t) { tasks.Add(t); }
}