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

const std::string &solution(const std::vector<std::string> &penguins);

int main() {
    int n;
    std::cin >> n;
    std::cin.clear();
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
    std::vector<std::string> penguins;
    penguins.reserve(n);
    for (int i = 0; i < n; ++i) {
        std::string penguin;
        std::getline(std::cin, penguin);
        penguins.emplace_back(std::move(penguin));
    }
    std::cout << solution(penguins) << std::endl;
    return 0;
}

const std::string &solution(const std::vector<std::string> &penguins) {
    std::set<std::string> penguinSet(penguins.begin(), penguins.end());
    auto setIterator = penguinSet.begin();
    std::set<std::string>::iterator mostNumerous;
    int maxCount = 0;
    while (setIterator != penguinSet.end()) {
        int count = 0;
        for (const auto &penguin : penguins) {
            if (*setIterator == penguin) {
                count++;
            }
        }
        if (count > maxCount) {
            maxCount = count;
            mostNumerous = setIterator;
        }
        setIterator++;
    }
    return *mostNumerous;
}

I tested locally and it works...