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

using namespace std;


class PRelation
{
	string name;
	
	public: 
		PRelation()
		{
			name = "~";
		}
		
		PRelation(string str)
		{
			name = str;
		}
		
		void setPRelation(string str)
		{
			name = str;
		}	
		string getName()
		{
			return name;
		}
};

class PAttribute
{
	string name;
	string type;
	string size;
	
	public:
		PAttribute()
		{
			name = "~";
			type = "~";
			size = "~";
		}
		
		PAttribute(string str, string t)
		{
			name = str;
			type = t;
			size = "~";
		}
		
		PAttribute(string str, string t, string s)
		{
			name = str;
			type = t;
			size = s;
		}
		
		void setPAttributeName(string str)
		{
			name = str;
		}
		
		void setPAttributeType(string t)
		{
			type = t;
		}
		
		void setPAttributeSize(string s)
		{
			size = s;
		}
		
		string getPAttribute()
		{
			return name;
		}
};

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

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

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

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

class PProjection
{
	string newName;
	string oldName;
	
	public:
		PProjection()
		{
			newName = "~";
			oldName = "~";
		}
		
		PProjection(string s1, string s2)
		{
			newName = s1;
			oldName = s2;
		}
		
		string doPProjection()
		{
			return "Projecting " + oldName + " onto " + newName;
		}
};

class POperand
{
	string op;
	
	public:
	
		POperand()
		{
			op = "~";
		}
		
		POperand(string str)
		{
			op = str;
		}
		
		void setPOperand(string str)
		{
			op = str;
		}
		
		string getPOperand()
		{
			return op;
		}
};

class POp
{
	string op;
	
	public: 
		POp()
		{
			op = "~";
		}
		
		POp(string str)
		{
			op = str;
		}
		
		void setPOp(string str)
		{
			op = str;
		}
		
		string getPOp()
		{
			return op;
		}
};

class PComparison
{
	POp op;
	POperand operand1;
	POperand operand2;
	
	public:
		PComparison()
		{
			op.setPOp("~");
			operand1.setPOperand("~");
			operand2.setPOperand("~");
		}
		
		PComparison(string str1, string str2, string str3)
		{
			operand1.setPOperand(str1);
			op.setPOp(str2);
			operand2.setPOperand(str3);
		}
		
		void setPComparison(string str1, string str2, string str3)
		{
			operand1.setPOperand(str1);
			op.setPOp(str2);
			operand2.setPOperand(str3);
		}
		
		string getPComparison()
		{
			return operand1.getPOperand() + " " + op.getPOp() + " " + operand2.getPOperand();
		}
};

class PConjunction
{
	string conj;
	public:
		PConjunction()
		{
			conj = "~";
		}
		
		PConjunction(string str)
		{
			conj = str;
		}
		
		void setPConjunction(string str)
		{
			conj = str;
		}
		
		string getPConjunction()
		{
			return conj;
		}
};

class PCondition
{
	string cond;
	public:
	
		PCondition()
		{
			cond = "~";
		}
	
		PCondition(string str)
		{
			cond = str;
		}
		
		void setPCondition(string str)
		{
			cond = str;
		}
		
		string getPCondition()
		{
			return cond;
		}
};

class PSelection
{
	string select;
	public:
		PSelection()
		{
			select = "~";
		}
		
		PSelection(string str)
		{
			select = str;
		}
		
		string getPSelection()
		{
			return select;
		}
};

class PExpression
{
	PRelation rel;
	PSelection sel;
	PProjection proj;
	PRenaming ren;
	PUnion un;
	PDifference diff;
	PProduct prod;
	string temp;
	
	public:
	
		PExpression()
		{
		}
	
		PExpression(string str)
		{
			temp = str;
		}
		
		void setPExpression(string str)
		{
			temp = str;
		}
		
		string getPExpression()
		{
			return temp;
		}
};