Cheese for Anfisa - 2#67
After cutting cheese in the problem «Cheese for Anfisa», the owner was left with pieces of cheese in the form of rectangular parallelepipeds with integer side lengths. To prepare a new dish for Anfisa, the owner needs to cut these pieces into cubes of side . At each step, only one piece can be cut, and each cut divides a piece into two parts. What is the minimum number of cuts required to divide the initial cheese piece into unit cubes?
The input contains one line with three integers , , (1 \leq a, b, c \leq 2 \cdot 10^9) — the side lengths of the cheese piece.
Print the minimum number of cuts required. It is guaranteed that this number does not exceed 10^{18}.
Example 1