04. Short Words

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

using namespace std;

int main() {
    string line, word;
    getline(cin, line);

    istringstream ss(line);

    set<string> words;

    while (ss >> word) {
        if (word.size() < 5) {
            for (int i = 0; i < word.size(); i++) {
                word[i] = tolower(word[i]);
            }
            words.insert(word);
        }
    }

    while (!words.empty()) {
        cout << *words.begin();
        words.erase(words.begin());
        if (!words.empty()) {
            cout << ", ";
        }
    }

    cout << endl;
    return 0;
}