How to calculate Net Income from Retained earnings?

Hi. I'm a Japanese learning Accounting in English, so I'm sorry if my English sentences sometimes don't make sense to you all.

I 'm trying to calculate 2013 Net Income of this company called "Nikon", using three financial statements provided in the link below. According to my professor, 2013 Net Income = 2013 Retained Earnings - 2012 Retained Earnings + Dividends paid. I tried this formula.

345,692(million Japanese yen) - 319,823 + 15,842=41,711

Based on my calculation, 2013 Net income should be 41,711 million JPY; however, the income statement from the link below says it's 42,459 million JPY.

http://nikon.com/about/ir/finance/financial_statements/index.htm

Anyone who knows Accounting, please help me figure out where I made a mistake?

I believe the amounts you are referring to are for the 3rd quarter of both 2013 and 2012. You'd need to use the beginning of the year retained earnings (i.e. Ending Q4) for the formula to work