Sliced On Exit

struct Base : std::exception {
    const char *what() const noexcept override { return "base"; }
};
struct Derived : Base {
    const char *what() const noexcept override { return "derived"; }
};

try { throw Derived{}; } catch (Base e)        { std::puts(e.what()); }
try { throw Derived{}; } catch (const Base &e) { std::puts(e.what()); }

What does this print?