English
Zadanie Liczba zbiorów n-k-specjalnych (liz)
The Number of N-k-special Sets
Memory limit: 32 MB
We say that a set 
of natural numbers is 
-
-special if:
- for every
we have 
,
- the sum of all integers from
is greater than 
,
-
does not contain a pair of consecutive natural numbers.
Task
Write a program that:
- reads two natural numbers
and 
from the standard input,
- computes the number of
-
-special sets,
- writes the result to the standard output.
Input
In the first line of the standard input there are two natural numbers 
and 
separated by a single space, 
, 
.
Output
In the first line of the standard output there should be written one non-negative integer,
which equals the number of 
-
-special sets for the given 
and 
.
Example
For the input data:
5 6
the correct result is:
3
Task author: Wojciech Rytter.