text: class Solution:
      """
      @param s: the string s
      @return: check if the string is interesting
      """
      def check(self, s):
          self.visited = set()
          return 'yes' if self.dfs(s, 0) else 'no'
  
      def dfs(self, s, start):
          if start in self.visited:
              return False
  
          if start > len(s):
              return False
  
          if start == len(s):
              return True
  
          result = False
          num = 0
          i = start
          while i < len(s) and s[i].isdigit():
              num = num * 10 + ord(s[i]) - ord('0')
              result = self.dfs(s, i + num + 1)
              if result:
                  return True
  
              i += 1
  
          self.visited.add(start)
          return result