text:  class Solution:
      def XXX(self, n: int) -> str:
          if n == 1: return '1'
          if n >= 2:
              s = self.XXX(n-1)
              conut = {}
              j=0
              res = []
              res.append(s[0])
              fi = ''
              conut.setdefault(0,1)
              for i in range(1,len(s)):
                  if s[i] == s[i-1]:
                      conut[j] += 1
                  else:
                      conut.setdefault(j+1,1)
                      j = j+1
                      res.append(s[i])
              for i in range(len(res)):
                  fi += str(conut[i])+res[i]
              return fi
  
  
  