Hamilton Pipeline#1864
The city of Namhetten is a rectangle of size m \times n, consisting of square blocks.
Engineer Hamilton wants to build a water supply in this city in the form of a closed pipe that passes under each block exactly once.
Under each block, the pipe can either go straight or turn at degrees.
How many different Hamilton pipeline plans are possible?
For example, for a city of size 4 \times 4, there are possible plans:
The input file contains the natural numbers and — the dimensions of Namhetten (1 \leq m \times n \leq 100).
Print one number — the number of possible Hamilton pipeline plans in this city.
Example 1