#include <iostream>
#include <string>

int chr2idx(char c) {
    return c - 'a';
}

struct Set;
Set empty_set();
Set singleton_set(char);
Set set_from_str(const char*);
bool is_in_set(char, Set);
Set union_set(Set, Set);
Set intersection_set(Set, Set);
Set diff_set(Set, Set);
std::string set_to_string(Set);

struct Set {
    long data;
    Set(long d): data(d) {}
};

Set empty_set() { return Set(0); }

Set singleton_set(char c) {
    return Set(1 << chr2idx(c));
}

Set set_from_str(const char* elems) {
    Set s = empty_set();
    while (*elems) s = union_set(s, singleton_set(*elems++));
    return s;
}

bool is_in_set(char c, Set s) {
    int i = chr2idx(c);
    return s.data & (1 << i);
}

Set union_set(Set a, Set b) { return Set(a.data | b.data); }

Set intersection_set(Set a, Set b) { return Set(a.data & b.data); }

Set diff_set(Set a, Set b) { return Set(a.data - intersection_set(a, b).data); }

std::string set_to_string(Set s) {
    std::string r;
    for (char i = 'a'; i <= 'z'; ++i) {
        if (is_in_set(i, s)) r.push_back(i);
    }
    return r;
}

std::string parse(std::string s) {
    std::string v;
    v.reserve(s.size());
    for (size_t i = 0; i < s.size(); ++i) {
        if ('a' <= s[i] && s[i] <= 'z') v.push_back(s[i]);
    }
    return v;
}

std::ostream& operator << (std::ostream& os, Set s) {
    os << set_to_string(s);
    return os;
}

int _tmain(int argc, _TCHAR* argv[])
{
    std::cout << "Set1 = ";
    std::string s1;
    std::getline(std::cin, s1);
    std::cout << "Set2 = ";
    std::string s2;
    std::getline(std::cin, s2);
    s1 = parse(s1);
    s2 = parse(s2);
    Set set1 = set_from_str(s1.c_str());
    Set set2 = set_from_str(s2.c_str());
    std::cout << "Set1 or Set2 = " << union_set(set1, set2) << std::endl
              << "Set1 and Set2 = " << intersection_set(set1, set2) << std::endl
              << "Set1 - Set2 = " << diff_set(set1, set2) << std::endl;
    std::cin >> s1;
    return 0;
}