import Data.List
 
reps m n = reverse [concat $ replicate m (show i) | i <- [1..n]]
 
res n = last $ take ((n-2)^2 + 1) $ iterate next (a0, b0) where
  a = concat $ [show $ n-1] ++ (reps (n-1) (n-1))
  a0 = concat $ reps 2 (n-1)
  b0 = a \\ a0
 
next (as, bs) = (as', bs') where
  as' = as ++ [b]
  bs' = bs \\ [b]
  b = findB as bs
 
findB as bs = b where
  b = if (ab `elem` digits) then (findB as (tail bs')) else (head bs') 
  digits = zipWith (\x y -> [x] ++ [y]) (init as) (tail as)
  ab = [a] ++ [head bs']
  a = last as
  bs' = sort $ nub bs
 
answer n = inits ++ tens ++ "0" where -- n進数での解
  inits = fst $ res n
  tens = tail . concat . map show . concat $ zipWith (\x y -> [x] ++ [y]) [n-1,n-2..1] [0,0..]
 
main = print $ answer 10

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