Pair : Type -> Type -> Type
Pair A B = { p1 : A; p2 : B }

pair : (A:Type) -> (B:Type) -> A -> B -> Pair A B
pair _ _ x y = { p1 = x; p2 = y }

fst : (A:Type) -> (B:Type) -> Pair A B -> A
fst _ _ p = case p of Pair _ _ x _ -> x

snd : (A:Type) -> (B:Type) -> Pair A B -> B
snd _ _ p = case p of Pair _ _ x _ -> x