466. Count The Repetitions

We define str = [s, n] as the string str which consists of the string s concatenated n times. - For example, str == ["abc", 3] =="abcabcabc". We define that string s1 can be obtained from string s2 if we can remove some characters from s2 such that it becomes s1. - For example, s1 = "abc" can be obtained from s2 = "abdbec" based on our definition by removing the bolded underlined characters. Y