Two different products are manufactured in two factories. The following incomplete table is known about the production quantities:

	FACTORY 1	FACTORY 2	TOTAL
PRODUCT 1			452
PRODUCT 2			868
TOTAL	717	603

In addition, it is known that a total of 723 units of product 1 were manufactured in factory 1 and product 2 in factory 2. How much product 1 was produced in factory 2? Note that although the rows and columns give a total of four equations, only three of them are linearly independent, so one can be omitted. The problem finally results in a linear equation group of four unknowns and four equations, which is solved by normal matrix calculation methods.