You are given two strings, pattern and value. The pattern string consists of just the letters a and b, describing a pattern within a string. For example, the string catcatgocatgo matches the pattern aabab (where cat is a and go is b). It also matches patterns like a, ab, and b. Write a method to determine if value matches pattern. a and b cannot be the same string.

Example 1:

Input:  pattern = "abba", value = "dogcatcatdog"
Output:  true

Example 2:

Input:  pattern = "abba", value = "dogcatcatfish"
Output:  false

Example 3:

Input:  pattern = "aaaa", value = "dogcatcatdog"
Output:  false

Example 4:

Input:  pattern = "abba", value = "dogdogdogdog"
Output:  true
Explanation:  "a"="dogdog",b=""，vice versa.

Note:

• 0 <= len(pattern) <= 1000
• 0 <= len(value) <= 1000
• pattern only contains "a" and "b", value only contains lowercase letters.