#include <iostream>

class Task {
	protected:
		int days;
		int task_revenue;
		double probability_of_success;

	public:
		Task();
		Task( int, int, double = 1.0 );
		int time() const;
		int revenue() const;
		double probability() const;
		virtual double priority() const = 0;
};

Task::Task():
days( 0 ),
task_revenue( 0 ),
probability_of_success( 0.0 ) {
	// Does nothing...
}

Task::Task( int d, int r, double p ):
days( std::max( 0, d ) ),
task_revenue( std::max( 0, r ) ),
probability_of_success( std::min( std::max( 0.0, p ), 1.0 ) ) {
	// Does nothing...
}

int Task::time() const {
	return days;
}

int Task::revenue() const {
	return task_revenue;
}

double Task::probability() const {
	return probability_of_success;
}

class Time : public Task {
	using Task::days;
	using Task::task_revenue;

	public:
		Time();
		Time( int, int, double = 1.0 );
		double priority() const;
};

Time::Time():
Task( 0, 0, 0.0 ) {
	// Does nothing...
}

Time::Time( int d, int r, double p ):
Task( d, r, p ) {
	// Does nothing...
}

double Time::priority() const {
	return -Task::time();
}

class Revenue : public Task {
	using Task::days;
	using Task::task_revenue;

	public:
		Revenue();
		Revenue( int, int, double = 1.0 );
		double priority() const;
};

Revenue::Revenue():
Task( 0, 0, 0.0 ) {
	// Does nothing...
}

Revenue::Revenue( int d, int r, double p ):
Task( d, r, p ) {
	// Does nothing...
}

double Revenue::priority() const {
	return -revenue();
}

class Revenue_density : public Task {
	using Task::days;
	using Task::task_revenue;

	public:
		Revenue_density();
		Revenue_density( int, int, double = 1.0 );
		double priority() const;
};

Revenue_density::Revenue_density():
Task( 0, 0, 0.0 ) {
	// Does nothing...
}

Revenue_density::Revenue_density( int d, int r, double p ):
Task( d, r, p ) {
	// Does nothing...
}

double Revenue_density::priority() const {
	return -static_cast<double>( revenue() )/static_cast<double>( time() );
}