chk g =
  let m = concat $ filter (\f -> length(f) > 1) $ map (\ n -> filter (\(i,v) -> v == n) g) [1..9]
  in
    m
chk g =
  let m = concat $ filter (\f -> length(f) > 1) $ map (\ n -> filter (\(i,v) -> v == n) g) [1..9]
  in
    m
chk g =
  let m = concat $ filter (\f -> length(f) > 1) $ map (\ n -> filter (\(i,v) -> v == n) g) [1..9]
  in
    m