public class Rational
{
    private int numerator;
    private int denominator;

    public Rational(int n, int d)
    {
        numerator = n;
        denominator = d;
    }

    public Rational add(Rational val)
    {
        int n = this.numerator*val.denominator + val.numerator*this.denominator;
        int d = this.denominator * val.denominator;

        return new Rational(n, d);
    }

    public Rational mul(Rational val)
    {
        int n = this.numerator*val.numerator;
        int d = this.denominator*val.denominator;

        return new Rational(n, d);
    }

    public Rational sub(Rational val)
    {
        int n = this.numerator*val.denominator - val.numerator*this.denominator;
        int d = this.denominator * val.denominator;

        return new Rational(n, d);
    }

    public Rational div(Rational val)
    {
        int n = this.numerator*val.denominator;
        int d = this.denominator*val.numerator;

        return new Rational(n, d);
    }

    public String toString()
    {
        return numerator + "/" + denominator;
    }

    public int numerator(){
        return numerator;
    }

    public int denominator(){
        return denominator;
    }

    public boolean equals(Rational r)
    {
        return (this.numerator*r.denominator - this.denominator*r.numerator) == 0;
    }
}