import Data.List
import Data.Array
import qualified Data.Set as S
import qualified Data.Map as M
main = interact $ format . solve . parse
format True = "POSSIBLE"
format False = "IMPOSSIBLE"
solve g0 = go S.empty [g0] where
    go _ [] = False
    go cl (s:q) | s `S.member` cl = go cl q
                | elems s == "12345678." = True
                | otherwise = go (S.insert s cl) (next s ++ q)
next g = map (move g hole) (adj hole) where
  Just hole = find ((== '.') . (g!)) (indices g)
move g dst src = g // [(src,'.'),(dst,g!src)]
adj (1,1) = [(2,3),(3,2)]
adj (1,2) = [(3,1),(3,3)]
adj (1,3) = [(2,1),(3,2)]
adj (2,1) = [(1,3),(3,3)]
adj (2,2) = []
adj (2,3) = [(1,1),(3,1)]
adj (3,1) = [(1,2),(2,3)]
adj (3,2) = [(1,1),(1,3)]
adj (3,3) = [(1,2),(2,1)]
parse = listArray ((1,1),(3,3)) . concat . lines