<p>We define <code>str = [s, n]</code> as the string <code>str</code> which consists of the string <code>s</code> concatenated <code>n</code> times.</p>
<ul>
<li>For example, <code>str == ["abc", 3] =="abcabcabc"</code>.</li>
</ul>
<p>We define that string <code>s1</code> can be obtained from string <code>s2</code> if we can remove some characters from <code>s2</code> such that it becomes <code>s1</code>.</p>
<ul>
<li>For example, <code>s1 = "abc"</code> can be obtained from <code>s2 = "ab<strong><u>dbe</u></strong>c"</code> based on our definition by removing the bolded underlined characters.</li>
</ul>
<p>You are given two strings <code>s1</code> and <code>s2</code> and two integers <code>n1</code> and <code>n2</code>. You have the two strings <code>str1 = [s1, n1]</code> and <code>str2 = [s2, n2]</code>.</p>
<p>Return <em>the maximum integer </em><code>m</code><em> such that </em><code>str = [str2, m]</code><em> can be obtained from </em><code>str1</code>.</p>