typ i = int
typ c = char
typ b = bool

fun bb(b1:int, b2:int): b =
    let
        fun bbb(d1:i, d2:i) : i = d1 + d2
    in
        let fun aa() : c = 'a'
            fun aaa(f:i) : i = 5 * 4 + 7 + 9 % 110
        in
            aaa(8) * bbb(2, 3)
    end,
    b1 >= b2
   end