#include <set>
#include <string>
#include <iostream>
using namespace std;
int main() {
set<string> s;
s.insert({"one"});
s.insert({"two"});
s.insert({"three"});
s.insert({"one"});
for (const auto &x : s) {
cout << x << ' ';
}
cout << endl;
return 0;
}
