#include <iostream>

class Trace {
    int id_;

public:
    explicit Trace(int id) : id_{id} {
        std::cout << "build " << id_ << '\n';
    }

    ~Trace() {
        std::cout << "destroy " << id_ << '\n';
    }
};

int main() {
    Trace outer{1};
    {
        Trace inner{2};
    }
    return 0;
}