#include <iostream>
#include <sstream>
using namespace std;



int gcf(int a, int b) {     //greatest common factor

	int nod = 1;
	for (int i = abs(a); i > 0; i--) {
		if (abs(a) % i == 0 && abs(b) % i == 0) {
			nod = i;
			break;
		}
	}
	return nod;
}

int lcm(int n1, int n2) //least common multiple
{
	return abs(n1) * abs(n2) / gcf(n1, n2);
}

class Rational {
public:
	Rational() {
		numerator = 0;
		denominator = 1;
	};
	Rational(int new_numerator, int new_denominator) {
	// solving probs with sign
		if (new_numerator == 0)
		{
			new_denominator = 1;
		}
		else if (new_numerator < 0 && new_denominator < 0)
		{
			new_numerator = new_numerator * (-1);
			new_denominator = new_denominator * (-1);
		}
		else if (new_numerator < 0 && new_denominator > 0)
		{
			sign = -1;
			new_numerator = new_numerator * (-1);
		}
		else if (new_numerator > 0 && new_denominator < 0)
		{
			sign = -1;
			new_denominator = new_denominator * (-1);
		}



		int greatest_common_factor = gcf(new_numerator, new_denominator);
		numerator = sign * new_numerator / greatest_common_factor;
		denominator = new_denominator / greatest_common_factor;

	};
	int Numerator() const {
		return numerator;
	};
	int Denominator() const {
		return denominator;
	};
private:
	int numerator;
	int denominator;
	int sign = 1;

};
Rational operator+(Rational& lhs, Rational& rhs) {  // надо чтобы в функцую lcm подавались только значения  > 0;
	if (lhs.Denominator() == rhs.Denominator())
	{
		return { lhs.Numerator() + rhs.Numerator(), lhs.Denominator()};
	}
	else {

		int least_common_multiple = lcm(lhs.Denominator(), rhs.Denominator());
		int k1,k2;
		k1 = least_common_multiple / lhs.Denominator();
		int new_lhs_numerator = lhs.Numerator() * k1;
		k2 = least_common_multiple / rhs.Denominator();
		int new_rhs_numerator = rhs.Numerator() * k2;
		return { new_lhs_numerator + new_rhs_numerator, lhs.Denominator()*k1};
	}
}
Rational operator-(Rational& lhs, Rational& rhs) {
	if (lhs.Denominator() == rhs.Denominator())
	{
		return { lhs.Numerator() - rhs.Numerator(), lhs.Denominator()};
	}
	else {
		int least_common_multiple = lcm(lhs.Denominator(), rhs.Denominator());
		int k1, k2;
		k1 = least_common_multiple / lhs.Denominator();
		int new_lhs_numerator = lhs.Numerator() * k1;
		k2 = least_common_multiple / rhs.Denominator();
		int new_rhs_numerator = rhs.Numerator() * k2;
		return { new_lhs_numerator - new_rhs_numerator, lhs.Denominator()*k1};
	}
}
bool operator==(const Rational& lhs, const Rational& rhs) {
	if ((lhs.Numerator() == rhs.Numerator()) && (lhs.Denominator() == rhs.Denominator()))
		return 1;
	else return 0;
}

Rational operator*(const Rational& lhs, const Rational& rhs) {
	int new_nominator = lhs.Numerator() * rhs.Numerator();
	int new_denominator = lhs.Denominator()*rhs.Denominator();
	return { new_nominator , new_denominator };
}

Rational operator/(const Rational& lhs, const Rational& rhs) { // (a/b) / (c/d) = (a * d) / (b * c)
	int new_nominator = lhs.Numerator() * rhs.Denominator();
	int new_denominator = lhs.Denominator() * rhs.Numerator();
	return { new_nominator , new_denominator };
}

ostream& operator<<(ostream& stream,const Rational& rational) {
	stream << rational.Numerator() << "/" << rational.Denominator();
	return stream;
}
istream& operator>>(istream& stream, Rational& rational) {
	int new_numerator, new_denominator;

	stream >> new_numerator;
	stream.ignore(1);
	stream >> new_denominator;
	 rational = Rational(new_numerator, new_denominator);
	return stream;
}
int main() {
	{
		ostringstream output;
		output << Rational(-6, 8);
		if (output.str() != "-3/4") {
			cout << "Rational(-6, 8) should be written as \"-3/4\"" << endl;
			return 1;
		}
	}

	{
		istringstream input("5/7");
		Rational r;
		input >> r;
		bool equal = r == Rational(5, 7);
		if (!equal) {
			cout << "5/7 is incorrectly read as " << r << endl;
			return 2;
		}
	}

	{
		istringstream input("5/7 10/8");
		Rational r1, r2;
		input >> r1 >> r2;
		bool correct = r1 == Rational(5, 7) && r2 == Rational(5, 4);
		if (!correct) {
			cout << "Multiple values are read incorrectly: " << r1 << " " << r2 << endl;
			return 3;
		}

		input >> r1;
		input >> r2;
		correct = r1 == Rational(5, 7) && r2 == Rational(5, 4);
		if (!correct) {
			cout << "Read from empty stream shouldn't change arguments: " << r1 << " " << r2 << endl;
			return 4;
		}
	}

	cout << "OK" << endl;
	return 0;
}