#include <algorithm>
#include <cassert>
#include <cstddef>
#include <iostream>
#include <sstream>
#include <string>
#define todo(msg)                                                              \
  std::cerr << msg << std::endl;                                               \
  assert(false);
// TODO: try to maximize rvalue usage to reuse resources
// "Use rvalue references to reuse the resources of temporaries when possible,
// particularly for binary operands."

class Integer {
  using byte = unsigned char;
  // bytes are litle endian
  byte *bytes;
  bool isNegative;
  std::size_t size;

public:
  Integer(long long num = 0)
      : bytes{new byte[sizeof(long long)]}, isNegative{num < 0},
        size{sizeof(long long)} {
    for (std::size_t i = 0; i < size; i++) {
      bytes[i] = num % 256;
      num /= 256;
    }
  }
  Integer(Integer const &rhs)
      : bytes{new byte[rhs.size]}, isNegative{rhs.isNegative}, size{rhs.size} {
    for (std::size_t i = 0; i < size; i++) {
      bytes[i] = rhs.bytes[i];
    }
  }
  Integer(Integer &&rhs)
      : bytes{rhs.bytes}, isNegative{rhs.isNegative}, size{rhs.size} {
    rhs.bytes = nullptr;
  }
  ~Integer() {
    delete[] bytes;
    bytes = nullptr;
  }
  Integer &operator=(Integer const &rhs) {
    delete[] bytes;

    bytes = new byte[rhs.size];
    size = rhs.size;
    isNegative = rhs.isNegative;
    for (std::size_t i = 0; i < size; i++) {
      bytes[i] = rhs.bytes[i];
    }
    return *this;
  }
  Integer &operator=(Integer &&rhs) {
    bytes = rhs.bytes;
    rhs.bytes = nullptr;
    size = rhs.size;
    isNegative = rhs.isNegative;
    return *this;
  }
  friend Integer &operator+=(Integer &lhs, Integer const &rhs) {
    todo("+=");
    return lhs;
  }
  friend Integer &operator-=(Integer &lhs, Integer const &rhs) {
    todo("-=");
    return lhs;
  }
  friend Integer &operator*=(Integer &lhs, Integer const &rhs) {
    Integer tmp = std::move(lhs);
    Integer tmp_r = rhs;
    lhs = 0;
    while (tmp_r > 0) {
      lhs += tmp;
      tmp_r -= 1;
    }
    return lhs;
  }
  friend Integer &operator/=(Integer &lhs, Integer const &rhs) {
    Integer tmp = std::move(lhs);
    lhs = 0;
    while (tmp > rhs) {
      tmp -= rhs;
      lhs += 1;
    }
    return lhs;
  }
  friend Integer &operator%=(Integer &lhs, Integer const &rhs) {
    while (lhs > rhs) {
      lhs -= rhs;
    }
    return lhs;
  }
  friend Integer operator+(Integer const &lhs, Integer const &rhs) {
    Integer ret{lhs};
    ret += rhs;
    return ret;
  }
  friend Integer operator-(Integer const &lhs, Integer const &rhs) {
    Integer ret{lhs};
    ret -= rhs;
    return ret;
  }
  friend Integer operator*(Integer const &lhs, Integer const &rhs) {
    Integer ret{lhs};
    ret *= rhs;
    return ret;
  }
  friend Integer operator/(Integer const &lhs, Integer const &rhs) {
    Integer ret{lhs};
    ret /= rhs;
    return ret;
  }
  friend Integer operator%(Integer const &lhs, Integer const &rhs) {
    Integer ret{lhs};
    ret %= rhs;
    return ret;
  }
  friend Integer operator%(Integer const &lhs, byte rhs) {
    if (lhs.size == 0 || lhs.bytes == nullptr) {
      return 0;
    }
    return lhs.bytes[0] % rhs;
  }
  friend Integer operator-(Integer const &val) {
    Integer ret = val;
    ret.isNegative = !ret.isNegative;
    return ret;
  }
  friend bool operator<(Integer const &lhs, Integer const &rhs) {
    Integer tmp = (lhs - rhs);
    return tmp.isNegative && tmp != 0;
  }
  friend bool operator>(Integer const &lhs, Integer const &rhs) {
    Integer tmp = (rhs - lhs);
    return tmp.isNegative && tmp != 0;
  }
  friend bool operator==(Integer const &lhs, Integer const &rhs) {
    todo("need to actually do a check for the case that one or both of them is "
         "0");
    return (rhs - lhs) == 0;
  }

  friend std::ostream &operator<<(std::ostream &lhs, Integer const &rhs) {
    if (rhs == 0) {
      lhs << 0;
      return lhs;
    }

    Integer discard = rhs;
    std::stringstream to_output{};
    while (discard != 0) {
      to_output << discard % 10;
      discard /= 10;
    }
    std::string out;
    to_output >> out;
    std::reverse(out.begin(), out.end());
    lhs << out;
    return lhs;
  }

  explicit operator unsigned long() {
    unsigned long ret = 0;
    for (std::size_t i = 0; i < std::min(size, sizeof(unsigned long)); i++) {
      ret += (static_cast<unsigned long>(this->bytes[i]) << (i * 8));
    }
    return ret;
  }
};

int main(void) {
  for (std::size_t i = 0; i <= 8584148901; i++) {
    unsigned long n = i * i;
    n = i + i;
    n = i - i;
    n = i / i;
  }
}