#include <iostream>
#include <vector>
#include <cinttypes>
#include <algorithm>

using std::vector;

class Set {
 private:
  vector<int64_t> data;

 public:
  Set() = default;
  explicit Set(const vector<int64_t> &data) {
    for (auto elem : data) {
      if (find(this->data.begin(), this->data.end(), elem)
          == this->data.end()) {
        this->data.push_back(elem);
      }
    }
  }
  void Add(int64_t element) {
    if (find(this->data.begin(), this->data.end(), element)
        == this->data.end()) {
      this->data.push_back(element);
    }
  }

  void Remove(int64_t element) {
    auto iter = find(this->data.begin(), this->data.end(), element);
    if (iter != this->data.end()) {
      this->data.erase(iter);
    }
  }

  [[nodiscard]] bool Contains(int64_t element) const {
    return find(this->data.begin(), this->data.end(), element)
        != this->data.end();
  }

  [[nodiscard]] vector<int64_t> Data() const {
    return data;
  }

  [[nodiscard]] Set Union(const Set &set) const {
    Set newSet(Data());
    for (auto elem : set.Data()) {
      newSet.Add(elem);
    }
    return newSet;
  }

  [[nodiscard]] Set Intersection(const Set &set) const {
    Set newSet;
    for (auto elem : set.Data()) {
      if (Contains(elem)) {
        newSet.Add(elem);
      }
    }
    return newSet;
  }

  [[nodiscard]] Set Difference(const Set &set) const {
    Set newSet;
    for (auto elem : Data()) {
      if (!set.Contains(elem)) {
        newSet.Add(elem);
      }
    }
    return newSet;
  }

  [[nodiscard]] Set SymmetricDifference(const Set &set) const {
    Set newSet = Difference(set);
    for (auto elem : set.Data()) {
      if (!Contains(elem)) {
        newSet.Add(elem);
      }
    }
    return newSet;
  }
};