import java.util.Scanner;

class frac{
    private int num, den;

    public frac(){
        this.num = 0;
        this.den = 1;
    }

    public frac(int num){
        this.num = num;
        this.den = 1;
    }

    public frac(int num, int den){
        this.num = num;
        if (den == 0){
            System.out.println("Error: Zero can not be a denominator");
        }
        this.den = den;
    }

    private int gcd(int a, int b){
        while (b != 0){
            int t = b;
            b = a % b;
            a = t;
        }
        return a;
    }

    private void reduction(){
        int nod = gcd(num, den);
        num /= nod;
        den /= nod;
    }

    public void plus(frac other){
        this.num = this.num * other.den + other.num * this.den;
        this.den *= other.den;
        reduction();
    }

    public void minus(frac other){
        this.num = this.num * other.den - other.num * this.den;
        this.den *= other.den;
        reduction();
    }

    public void mult(frac other){
        this.num *= other.num;
        this.den *= other.den;
        reduction();
    }

    public void div(frac other){
        frac other1 = new frac(other.den, other.num);
        mult(other1);
        reduction();
    }

    public String vyvod(){
        return num + "/" + den;
    }

}