class MatrixMultiply
    {

        public int[,] MatrixMultEasy(int[,] left, int[,] right)
        {
            int[,]Matrix = new int[left.GetLength(0), right.GetLength(1)];

            for (int i = 0; i < left.GetLength(0); i++)
            {
                for (int j = 0; j < right.GetLength(1); j++)
                {
                    int sum = 0;

                    for (int k = 0; k < right.GetLength(0); k++)
                    {
                        sum += left[i, k] * left[k, j];
                    }

                    Matrix[i, j] = sum;
                }

            }

            return (Matrix);

        }

        public bool CheckOnCorrect(int[,] left, int[,] right)
        {
            if ((left != null) && (right != null))
            {
                if (left.GetLength(1) != right.GetLength(0))
                {
                    return (false);
                }
                else
                {
                    return (true);
                }
            }
            else
            {
                return (false);
            }
        }
    }

    class MatrixSum
    {
        public int[,] Do(int[,] left, int[,] right)
        {

            for (int i = 0; i < left.GetLength(0); i++)
            {
                for (int j = 0; j < right.GetLength(1); j++)
                {
                    left[i, j] += right[i, j];
                }
            }

            return (left);
        }

        public bool CheckOnCorrect(int[,] left, int[,] right)
        {
            if ((left != null)&&(right != null))
            {

                if ((left.GetLength(0) == right.GetLength(0)) && (left.GetLength(1) == right.GetLength(1)))
                {
                    return (true);
                }
                else
                {
                    return (false);
                }
            }
            else
            {
                return (false);
            }
        }
    }
}