Multiset is a mathematical object similar to a set,
but each member of a multiset may have more than one membership.
Just as with any set, the members of a multiset can be ordered
in many ways. We call each such ordering a permutation
of the multiset. For example, among the permutations of the
multiset
there are
and
.
We will say that one permutation of a given multiset is smaller (in lexicographic order) than another permutation, if on the first position that does not match the first permutation has a smaller element than the other one. All permutations of a given multiset can be numbered (starting from one) in an increasing order.
Write a programme that
from the standard input,
,
The first line of the standard input holds two integers
and
(
,
), separated by
a single space. These denote, respectively, the cardinality of the
multiset and \dots\ the number
.
The second line of the standard input contains
positive integers
(
), separated by single spaces and denoting
successive elements of the multiset permutation.
The first and only line of the standard output is to hold one integer,
the remainder modulo
of the rank of the input permutation in the
lexicographic ordering.
For the input data:
4 1000 2 1 10 2
the correct result is:
5
All the permutations smaller (with respect to lexicographic order) than
the one given are:
,
,
and
.
Task author: Jakub Radoszewski.
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