CF845E Fire in the City

The capital of Berland looks like a rectangle of size $ n×m $ of the square blocks of same size. Fire! It is known that $ k+1 $ blocks got caught on fire ( $ k+1

The first line contains three integers $ n $ , $ m $ and $ k $ ( $ 1

Print the minimal time it takes the fire to lighten up the whole city (in minutes).

In the first example the last block can have coordinates $ (4,4) $ . In the second example the last block can have coordinates $ (8,3) $ .