What does this C++ snippet output?

1#include <iostream>
2#include <memory>
3struct A {
4  virtual void f() { std::cout << "A\n"; }
5  virtual ~A() = default;
6};
7struct B : A {
8  void f() override { std::cout << "B\n"; }
9};
10int main() {
11    std::unique_ptr<A> p = std::make_unique<B>();
12    p->f();
13}