module Main where

import Control.Monad (replicateM, replicateM_)
import Data.List (sort, transpose)

rowsums :: [[Integer]] -> [Integer]
rowsums = map sum

colsums :: [[Integer]] -> [Integer]
colsums rows = map sum (transpose rows)

testsums :: [[Integer]] -> Bool
testsums rows = sort (rowsums rows) == sort (colsums rows)

main :: IO ()
main = do
    cases <- readLn :: IO Int
    replicateM_ cases $ do
        n <- readLn :: IO Int
        rows <- replicateM n $ map read . words <$> getLine :: IO [[Integer]]
        putStrLn $ if testsums rows then "Possible" else "Impossible"