We define str = [s, n] as the string str which consists of the string s concatenated n times. We define that string s1 can be obtained from string s2 if we can remove some characters from s2 such that it becomes s1. You are given two strings s1 and s2 and two integers n1 and n2. You have the two strings str1 = [s1, n1] and str2 = [s2, n2]. Return the maximum integer m such that str = [str2, m] can be obtained from str1.