The definition of a good string is that its length is n, the Lexicographic order order is greater than or equal to s1, and the Lexicographic order order is less than or equal to s2, and the string does not contain an evil as a substring. Based on known data, specific numbers can be obtained; Use some data from circles and rectangles to determine whether there is overlap; The satisfaction level of cooking can be obtained by cooking certain dishes in the corresponding order to obtain a larger total; If a string does not contain any strings such as aaa , bbb , or ccc as substrings, then the string is a happy string.