import Data.List

q = 10^9+7

comb n r = iterate (scanl1 (+)) [1,1..] !! (n'-r') !! r'
 where [n',r'] = map fromIntegral [n,r]

main = getContents >>= print . kadomatsu . map read . words

kadomatsu :: [Integer] -> Integer
kadomatsu (n:as) = mod (comb n 3 - dup) q
 where
  dup = sum $ map comb' $ filter (>1) $ map (fromIntegral . length) $ group $ sort as
  comb' m
   | m==2 = n - m
   | otherwise = comb m 2 * (n-m) + comb m 3