import Data.List
import Data.Char

f1 :: Int -> Bool
f1 1 = False
f1 0 = True
f1 x
  | x `mod` 2 == 0 = True
  | x `mod` 3 == 0 = True
  | x `mod` 5 == 0 = True
  | otherwise = False

head2 :: [a] -> (a,a)
head2 [x,y] = (x,y)
head2 (x:xs) = (x,head xs)

ratAdd :: (Int, Int) -> (Int, Int) -> (Int, Int)
ratAdd (x,y) (z,w) = (w * x + y*z, y*w)

fac :: Int -> Int
fac 0 = 1
fac n = n * (fac (n -1))

minimumInt :: [Int] -> Int
minimumInt [x] = x
minimumInt [x,y] = x
minimumInt (x:xs) = head(sort(x:xs))

insert :: Int -> a -> [a] -> [a]
insert x y z = take x z ++ y : drop x (z)

minimumOfMaxima :: Ord a => [[a]] -> a
minimumOfMaxima [x:xs]= minimum(maximum [x:xs])
-- ez csak két eleműre működik

safeHead :: [a] -> Maybe a
safeHead [] = Nothing
safeHead x =Just (head x)