The biggest event of the year ended tragically for Croatian teams. The most influential
theoretician of CERC of all time, the founder of the popular page CERC Tips, and in his free
time an outstanding bass player, in his most recent performance failed to get his team to the
finals.
In order to get over his existential troubles, our subject is spending time playing games of
chance. He is especially interested in the following game:
You are given a positive integer \(M\). Our protagonist sees in front of him a permutation of an
array of numbers 0, 1, 2, ..., \(2^{M} - 1\).
The computer chooses a nonempty contiguous subsequence of the given permutation,
which it then lights up over a capital city of one of the countries in Southeastern Europe.
Our confidant, after fighting off tears caused by memories of old times, must choose two
distinct elements of the permutation and swap their places. Our man of the hour wins if and
only if the bitwise XOR of the numbers in the lit up subsequence after the substitution is
precisely \(2^{M} - 1\).
Our hero wants to know the number of contiguous subsequences the computer can light
up so that he can win.
Help our hero overcome his (id)entity crisis so our favourite page can be fully active again.

In test cases worth 50% of total points, it will hold \(1 \le M \le 14\).

The first line of input contains the integer \(M\) (\(1 \le M \le 20\)),
The following line contains \(2^{M}\) spa\(ce-se\)parated numbers that make up a permutation of the
array 0, 1, 2, ..., \(2^{M} - 1\).

You must output the total number of contiguous subsequences that a computer can light up
so our hero can win.

생성자가 기록되지 않았습니다.

출처 COCI 2017/2018 Contest 3