text: class Solution:
      def firstUniqChar(self, s):
          """
          :type s: str
          :rtype: int
          """
          
          letters = 'abcdefghijklmnopqrstuvwxyz'
          index = []
          
          for l in letters:
              if (s.count(l) == 1):
                  index.append(s.index(l))
          
          if (len(index) > 0):
              return min(index)  
          else:
              return -1
  