#include <vector>
#include <cstdint>

class Set {
 public:
    Set() = default;

    explicit Set(const std::vector<int64_t>&);

    Set Union(const Set &) const;

    Set Intersection(const Set &) const;

    Set Difference(const Set &) const;

    Set SymmetricDifference(const Set &) const;

    void Add(int64_t);

    void Remove(int64_t);

    bool Contains(int64_t) const;

    std::vector<int64_t> Data() const;

 private:
    std::vector<int64_t> vector;
};

Set::Set(const std::vector<int64_t> &vector) {
    for (auto const obj : vector)
        this->Add(obj);
}

Set Set::Union(const Set &old) const {
    Set new_set;
    for (auto const obj : old.Data())
        new_set.Add(obj);
    for (auto const obj : this->vector)
        new_set.Add(obj);
    return new_set;
}

Set Set::Intersection(const Set &another) const {
    Set new_set;
    for (auto const obj1 : this->vector)
        for (auto const obj2 : another.Data())
            if (obj1 == obj2)
                new_set.Add(obj1);
    return new_set;
}

Set Set::Difference(const Set &another) const {
    Set new_set;
    bool temp;
    for (auto const obj1 : this->vector) {
        temp = true;
        for (auto const obj2 : another.Data())
            if (obj1 == obj2) {
                temp = false;
                break;
            }
        if (temp)
            new_set.Add(obj1);
    }
    return new_set;
}

Set Set::SymmetricDifference(const Set &another) const {
    return this->Difference(another).Union(another.Difference(*this));
}

void Set::Add(int64_t num) {
    for (auto const obj : this->vector)
        if (obj == num)
            return;
    this->vector.push_back(num);
}

void Set::Remove(int64_t num) {
    for (unsigned int i = 0; i < this->vector.size(); i++)
        if (this->vector[i] == num) {
            this->vector.erase(this->vector.begin() + i);
            break;
        }
}

bool Set::Contains(int64_t num) const {
    for (auto const obj : this->vector)
        if (obj == num)
            return true;
    return false;
}

std::vector<int64_t> Set::Data() const {
    return this->vector;
}