#include <string>       // std::string
#include <iostream>     // std::cout
#include <sstream>      // std::stringstream
#include <vector>
#include <string>

using namespace std;


class Relation
{
	string name;
	
	public: 
		Relation()
		{
			name = NULL;
		}
		
		Relation(string str)
		{
			name = str;
		}
		
		void setRelation(string str)
		{
			name = str;
		}	
		string getName()
		{
			return name;
		}
};

class Attribute
{
	string name;
	
	public:
		Attribute()
		{
			name = NULL;
		}
		
		Attribute(string str)
		{
			name = str;
		}
		
		void setAttribute(string str)
		{
			name = str;
		}
		
		string getAttribute()
		{
			return name;
		}
};

class Union
{
	string Un1;
	string Un2;
	
	public:
		Union()
		{
			Un1 = NULL;
			Un2 = NULL;
		}
		
		Union (string s1, string s2)
		{
			Un1 = s1;
			Un2 = s2;
		}
		
		string getUnion()
		{
			return "Union of " + Un1 + " and " + Un2;
		}
};

class Product
{
	string Pr1;
	string Pr2;
	
	public:
		Product()
		{
			Pr1 = NULL;
			Pr2 = NULL;
		}
		
		Product(string s1, string s2)
		{
			Pr1 = s1;
			Pr2 = s2;
		}
		
		string getProduct()
		{
			return "Product of " + Pr1 + " and " + Pr2;
		}
};

class Difference
{
	string D1;
	string D2;
	
	public:
		Difference()
		{
			D1 = NULL;
			D2 = NULL;
		}
		
		Difference(string s1, string s2)
		{
			D1 = s1;
			D2 = s2;
		}
		
		string getDifference()
		{
			return "Difference of " + D1 + " and " + D2;
		}
};

class Renaming
{
	string newName;
	string oldName;
	
	public:
		Renaming()
		{
			newName = NULL;
			oldName = NULL;
		}
		
		Renaming(string s1, string s2)
		{
			newName = s1;
			oldName = s2;
		}
		
		string doRename()
		{
			return "Renaming " + oldName + " to " + newName;
		}
};

class Projection
{
	string newName;
	string oldName;
	
	public:
		Projection()
		{
			newName = NULL;
			oldName = NULL;
		}
		
		Projection(string s1, string s2)
		{
			newName = s1;
			oldName = s2;
		}
		
		string doProjection()
		{
			return "Projecting " + oldName + " onto " + newName;
		}
};

class Operand
{
	string op;
	
	public:
	
		Operand()
		{
			op = NULL;
		}
		
		Operand(string str)
		{
			op = str;
		}
		
		void setOperand(string str)
		{
			op = str;
		}
		
		string getOperand()
		{
			return op;
		}
};

class Op
{
	string op;
	
	public: 
		Op()
		{
			op = NULL;
		}
		
		Op(string str)
		{
			op = str;
		}
		
		void setOp(string str)
		{
			op = str;
		}
		
		string getOp()
		{
			return op;
		}
};

class Comparison
{
	Op op;
	Operand operand1;
	Operand operand2;
	
	public:
		Comparison()
		{
			op = NULL;
			operand1 = NULL;
			operand2 = NULL;
		}
		
		Comparison(string str1, string str2, string str3)
		{
			operand1.setOperand(str1);
			op.setOp(str2);
			operand2.setOperand(str3);
		}
		
		void setComparison(string str1, string str2, string str3)
		{
			operand1.setOperand(str1);
			op.setOp(str2);
			operand2.setOperand(str3);
		}
		
		string getComparison()
		{
			return operand1.getOperand() + " " + op.getOp() + " " + operand2.getOperand();
		}
};

class Conjunction
{
	string conj;
	public:
		Conjunction()
		{
			conj = NULL;
		}
		
		Conjunction(string str)
		{
			conj = str;
		}
		
		void setConjunction(string str)
		{
			conj = str;
		}
		
		string getConjunction()
		{
			return conj;
		}
};

class Condition
{
	string cond;
	public:
	
		Condition()
		{
			cond = NULL;
		}
	
		Condition(string str)
		{
			cond = str;
		}
		
		void setCondition(string str)
		{
			cond = str;
		}
		
		string getCondition()
		{
			return cond;
		}
};

class Selection
{
	string select;
	public:
		Selection()
		{
			select = NULL;
		}
		
		Selection(string str)
		{
			select = str;
		}
		
		string getSelection()
		{
			return select;
		}
};

class Expression
{
	string exp;
	
	public:
	
		Expression()
		{
			exp = NULL;
		}
	
		Expression(string str)
		{
			exp = str;
		}
		
		void setExpression(string str)
		{
			exp = str;
		}
		
		string getExpression()
		{
			return exp;
		}
};