#include <iostream>
#include <set>
#include <string>

int main() {
    std::set<std::string> zones{"West", "East"};
    auto [position, inserted] = zones.insert("West");
    std::cout << "Duplicate added: " << inserted << "; existing: " << *position << '\n';
    for (const auto& zone : zones) { std::cout << zone << '\n'; }
}