Problems
Paint3D
Paint3D
Figures 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 data
In the input file contains the number of A, B, C. 1 ≤ A, B, C ≤ 100.
Output data
The output file to write the answer - the smallest number of operations.
Examples
Input example #1
2 3 4
Output example #1
20