import re
let f=proc(s=""):bool=0>s.find re"(.)(?!\1).*\1"

const Tests = [
  "3",
  "51",
  "44999911",
  "123456789",
  "222222222222222222222",

  "818",
  "8884443334",
  "4545",
  "554553",
  "1234567891",
]

for s in Tests:
  echo f(s)