class Matrix
{
	int rows;
	int cols;
	int **MT;
public:
	Matrix(const Matrix &M);
	Matrix(int Rows=0, int Cols=0);
	Matrix();
	~Matrix();
	const Matrix & operator=(const Matrix &M);
	friend Matrix operator+(const Matrix,const Matrix);
	friend Matrix operator-(const Matrix,const Matrix);
	friend Matrix operator*(const Matrix,const Matrix);
	friend ostream& operator<<(ostream &, const Matrix &);
	friend istream& operator>>(istream &, Matrix &);
};
 
Matrix::Matrix(int Rows, int Cols)
{
	rows=Rows;
	cols=Cols;
	MT=new int *[rows];
	for(int i=0; i<rows; i++)
		MT[i]=new int[cols];
}

Matrix::~Matrix()
{
	//what is source code here ???
}