calendar2015 :: [(Int, Int)]
calendar2015 = [(1,31), (2,28), (3,31), (4,30), (5,31), (6,30), (7,31), (8,31), (9,30), (10,31), (11,30), (12,31)]

happyDay :: Int -> Int -> Bool
happyDay m d
    | m == d_10 + d_01  = True
    | otherwise         = False
    where
        d_10 = floor $ (fromIntegral (d :: Int)) / 10.0
        d_01 = d - d_10 * 10


happyDayCounter :: [(Int, Int)] -> Int
happyDayCounter [] = 0
happyDayCounter (c:cs) =
    do
        let
            m = fst c
            d = snd c
            days = [1..d]
        happyDayCounter' m days + happyDayCounter cs
    where
        happyDayCounter' :: Int -> [Int] -> Int
        happyDayCounter' _ [] = 0
        happyDayCounter' m (d:ds) -- = cnt + happyDayCounter' m ds
            | happyDay m d == True  = happyDayCounter' m ds + 1
            | otherwise             = happyDayCounter' m ds

main = print $ happyDayCounter calendar2015