set 2

#include <iostream>
#include <fstream>
#include <set>
#include <vector>
#include <string>
#include <iterator>
#include <algorithm>
using namespace std;
ifstream in("input.txt");
ofstream out("output.txt");

int main()
{
    string s;
    vector <string> v, result;
    multiset <char> set1, set2;
    set <string> U;

    while (!in.eof())
    {
        getline(in, s);
        v.push_back(s);
    }

    for (int i = 0; i < v.size(); i++)
    {
        set <char> c1 = { '?' };
        set <char> c2 = { '!' };
        for (int j = 0; j < s.length(); j++)
        {
            if ((ispunct(s[j])) && (c1.count(s[j]) == 1))
            {
                for (int k = 0; k < j; k++)
                {
                    set1.insert(s[k]);
                }
            }
            if ((ispunct(s[j])) && (c2.count(s[j]) == 1))
            {
                for (int h = 0; h < j; h++)
                {
                    set2.insert(s[h]);
                }
            }
        }
    }
    set<string>::iterator it;
    set_intersection(set1.begin(), set1.end(), set2.begin(), set2.end(), inserter(U, U.begin()));
    for (auto it : U)
    {
        out << it << endl;
    }
    return 0;
}