Given a list of
integers, compute the number of triples
with
such that the median of
,
, and
is
.
Constraints
Input Specification
The first line of the input consists of two space-separated integers, and
.
The next line contains space-separated integers, the values
through
representing
the
numbers of the list in order.
Output Specification
Output, on a single line, the number of valid triples.
Sample Input
4 1
1 1 2 2
Sample Output
2
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