Задача 7

#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <map>
using namespace std;



ifstream fin("input.txt");
ofstream out("output.txt");

int main()
{
    map<string, int> a;
    vector<string> b;
    while (fin.peek() != EOF)
    {
        string s;
        fin >> s;
        b.push_back(s);
        a[s]++;
    }
    for (int i = 0; i < b.size(); ++i)
    {
        if (a[b[i]] == 1)
            out << b[i] << endl;
    }
}