如何在multimap c++中删除重复读取值？

#include <iostream>
#include <map>

int main() {
    std::multimap<int, std::string> myMultimap;
    myMultimap.insert(std::make_pair(1, "apple"));
    myMultimap.insert(std::make_pair(2, "banana"));
    myMultimap.insert(std::make_pair(3, "apple"));
    myMultimap.insert(std::make_pair(4, "orange"));
    myMultimap.insert(std::make_pair(5, "banana"));

    std::multimap<int, std::string> uniqueMultimap;
    for (auto it = myMultimap.begin(); it != myMultimap.end(); ++it) {
        if (uniqueMultimap.find(it->first) == uniqueMultimap.end()) {
            uniqueMultimap.insert(*it);
        }
    }

    myMultimap = uniqueMultimap;

    // 输出删除重复读取值后的multimap
    for (auto it = myMultimap.begin(); it != myMultimap.end(); ++it) {
        std::cout << it->first << ": " << it->second << std::endl;
    }

    return 0;
}

1: apple
2: banana
4: orange