<p>Given an array of integers&nbsp;<code>arr</code>&nbsp;and an integer <code>k</code>.&nbsp;Find the <em>least number of unique integers</em>&nbsp;after removing <strong>exactly</strong> <code>k</code> elements<b>.</b></p>



<ol>

</ol>



<p>&nbsp;</p>

<p><strong>Example 1:</strong></p>



<pre>

<strong>Input: </strong>arr = [5,5,4], k = 1

<strong>Output: </strong>1

<strong>Explanation</strong>: Remove the single 4, only 5 is left.

</pre>

<strong>Example 2:</strong>



<pre>

<strong>Input: </strong>arr = [4,3,1,1,3,3,2], k = 3

<strong>Output: </strong>2

<strong>Explanation</strong>: Remove 4, 2 and either one of the two 1s or three 3s. 1 and 3 will be left.</pre>



<p>&nbsp;</p>

<p><strong>Constraints:</strong></p>



<ul>

	<li><code>1 &lt;= arr.length&nbsp;&lt;= 10^5</code></li>

	<li><code>1 &lt;= arr[i] &lt;= 10^9</code></li>

	<li><code>0 &lt;= k&nbsp;&lt;= arr.length</code></li>

</ul>