#include <string>

class pair
{
		std::string m_left;
		double m_right;
		
	public:
		pair();
		pair(std::string s, double x);
		const std::string& left() const;
		std::string& left();
		const double& right() const;
		double& right();
		pair& operator+=(const pair& other);
};

pair operator+(const pair& a, const pair& b);