1. Reporter

#include <iostream>
#include <string>
#include <sstream>
#include <unordered_set>

using namespace std;

string readInput()
{
    string result;
    int numberOfLines;
    cin >> numberOfLines;
    cin.ignore();

    for (int i = 0; i < numberOfLines; i++)
    {
        string line;
        getline(cin, line);

        result = result + line + " ";
    }
    return result;
}

void cleanSentence(string &text)
{
    istringstream istr(text);
    unordered_set<string> set;
    string outText;

    do {
        string word;
        istr >> word;

        while (set.find(word) == set.end())
        {
            outText = outText + word + " ";
            set.insert(word);
        }

    } while (istr);
    outText.erase(outText.size() - 1);
    cout << outText;
}

void makeSentence(string &text)
{
    istringstream istr(text);
    string word;
    string output;

    while (istr >> word)
    {
        output = output + word + " ";
        if (word == "." )
        {
            cleanSentence(output);
            output = "";
        }
    }
    cleanSentence(output);
}

int main()
{
    string inputText = readInput();

    makeSentence(inputText);

    return 0;
}