#include <iostream>
#include <string>
#include <vector>

using namespace std;


struct Token
{
	string data;
};

struct TokenReader
{
	virtual bool ReadNext(char c) = 0;
protected:
	string receiveBuffer;
	void Store(char c)
	{
		receiveBuffer += c;
	}
};

struct IdentifierTokenReader : public TokenReader
{
	virtual bool ReadNext(char c) override
	{
		bool next = (IsFirstChar() && IsLetter(c)) || (!IsFirstChar() && (IsLetter(c) || IsDigit(c)));
		if (next)
			Store(c);

		return next;
	}
private:
	bool IsLetter(char c) const
	{
		return c >= 'a' && c <= 'z';
	}
	bool IsDigit(char c) const
	{
		return c >= '0' && c <= '9';
	}
	bool IsFirstChar() const
	{
		return receiveBuffer.empty();
	}
};

struct LeftParenthesis : TokenReader
{
	virtual bool ReadNext(char c) override
	{
		return false;
	}
};

struct TokenNode
{
	string Id;
	vector<TokenNode> next;
};

int main()
{

	return 0;
}