#include <iostream>

class Rational {
 public:
  // Constructor
  Rational(int numerator = 0, int denominator = 1)
      : numerator_(numerator), denominator_(denominator) {}

  // Accessor functions
  int numerator() const { return numerator_; }
  int denominator() const { return denominator_; }

  // Member operators
  Rational operator-() const {
    return Rational(-numerator_, denominator_);
  }

  Rational& operator++() {
    numerator_ += denominator_;
    return *this;
  }

  Rational operator++(int) {
    Rational result = *this;
    ++*this;
    return result;
  }

 private:
  int numerator_;
  int denominator_;
};

// Non-member operators
Rational operator+(const Rational& lhs, const Rational& rhs) {
  return Rational(
      lhs.numerator() * rhs.denominator() + rhs.numerator() * lhs.denominator(),
      lhs.denominator() * rhs.denominator());
}

Rational operator-(const Rational& lhs, const Rational& rhs) {
  return lhs + (-rhs);
}

Rational operator*(const Rational& lhs, const Rational& rhs) {
  return Rational(lhs.numerator() * rhs.numerator(),
                  lhs.denominator() * rhs.denominator());
}

Rational operator/(const Rational& lhs, const Rational& rhs) {
  return Rational(lhs.numerator() * rhs.denominator(),
                  lhs.denominator() * rhs.numerator());
}

bool operator==(const Rational& lhs, const Rational& rhs) {
  return lhs.numerator() == rhs.numerator() &&
         lhs.denominator() == rhs.denominator();
}

bool operator!=(const Rational& lhs, const Rational& rhs) {
  return !(lhs == rhs);
}

int main() {
  Rational a(2, 3);
  Rational b(4, 5);
  Rational c = a + b;
  Rational d = a - b;
  Rational e = a * b;
  Rational f = a / b;

  std::cout << a.numerator() << '/' << a.denominator() << '\n';
  std::cout << b.numerator() << '/' << b.denominator() << '\n';
  std::cout << c.numerator() << '/' << c.denominator() << '\n';
  std::cout << d.numerator() << '/' << d.denominator() << '\n';
  std::cout << e.numerator() << '/' << e.denominator() << '\n';
  std::cout << f.numerator() << '/' << f.denominator() << '\n';
}