<p>You are given two strings <code>s</code> and <code>t</code>.</p>

<p>String <code>t</code> is generated by random shuffling string <code>s</code> and then add one more letter at a random position.</p>

<p>Return the letter that was added to <code>t</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;abcd&quot;, t = &quot;abcde&quot;
<strong>Output:</strong> &quot;e&quot;
<strong>Explanation:</strong> &#39;e&#39; is the letter that was added.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;&quot;, t = &quot;y&quot;
<strong>Output:</strong> &quot;y&quot;
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>0 &lt;= s.length &lt;= 1000</code></li>
	<li><code>t.length == s.length + 1</code></li>
	<li><code>s</code> and <code>t</code> consist of lowercase English letters.</li>
</ul>

class Solution:
    def findTheDifference(self, s: str, t: str) -> str:
        s=list(s)
        t=list(t)
        for i in t:
            if i not in s:
                return i
            if i in s:
                s[s.index(i)]="-"
        
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