For his gift, Inaho got a grid of square cells, initially all white. He wants to colour exactly cells black such that no two black cells are adjacent. Two cells are adjacent if they share a common side (so two cells which share only a corner are not adjacent). Output the number of ways to do this modulo .
Constraints
- In test cases worth 25% of points, .
- In test cases worth 25% of points, .
- In test cases worth 50% of points, .
In all test cases, .
Input Specification
The first and only line of input will contain and separated by a space.
Output Specification
A single line containing the answer.
Sample Input 1
1 2
Sample Output 1
6
Sample Input 2
3 3
Sample Output 2
215
Sample Input 3
420 50
Sample Output 3
763771419
Sample Input 4
2015 0
Sample Output 4
1
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