e-olymp
Problems

Paint3D

Paint3D

prb25Figures on a sheet of photo editor PAІNT can select and copy (in full), paste and move (drag). What is the smallest number of such operations should be used to having an image on a sheet of the unit cube, to build another image - a cuboid with dimensions AxBxC made up of these cubes?

Input

In the input file contains the number ofA, B, C. 1A, B, C100.

Output

The output file to write the answer - the smallest number of operations.

Time limit 1 second
Memory limit 64 MiB
Input example #1
2 3 4
Output example #1
20
Author Сергей Матвийчук