create a sitting arrangement using javascript(node.js) : <p>I have given a row of seats. Each seat is either occupied by a woman (denoted by xx) or a man (denoted by xy).</p>

<p>The objective is to find the minimum number of seat exchanges required such that the men and women are seated alternately.</p>

<p><strong>Input Format</strong></p>

<p>The first line of input consists of an integer <code>t</code> denoting the number of test cases. <code>t</code> test cases follow. Each test case consists of two lines. The first line of each test case consists of an integer n denoting the number of seats. Second line consists of n space separated tokens, each token denoting the occupant of that particular seat.</p>

<p><strong>Output Format</strong></p>

<p>For each test case, print the number of seat exchanges required. If an alternate seating is impossible, print -1.</p>

<p><strong>Sample Input</strong></p>

<pre><code>5
3
xx xx xx
2
xx xy
4
xx xx xy xy
8
xx xx xy xy xy xx xx xy
7
xx xy xx xy xx xy xy
</code></pre>

<p><strong>Sample Output</strong></p>

<pre><code>-1
0
1
2
3
</code></pre>

<p>Constraints
1 &lt;= t &lt;= 1000</p>

<p>1 &lt;= n &lt;= 10000</p>

<p><strong>Explanation</strong>
For xx xx xy xy, one can exchange seat 1 with seat 4 giving xy xx xy xx giving an alternate seating arrangement.</p>
