Consider an array where each integer from to
(inclusive) can be made by either adding or subtracting
numbers in the array. More rigorously, for every integer
there exists two indices
such that
or
. Furthermore, each array element must be an integer in the range
, though they do not have to be distinct.
Your goal is to find and construct such an array with a length of at most .
Constraints
Points Awarded | ||
---|---|---|
6 points | ||
9 points |
Input Specification
The only line of input contains two integers and
.
Output Specification
The first line should contain an integer , the length of the array
you have found.
The next line should contain integers
, the elements of the array.
Sample Input
18 7
Sample Output
7
2 3 16 4 8 5 13
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