import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;

class RN {
   private int numerator;
   private int denominator;

   // default constructor -- need it because you
   // might define other constructors
   public RN() {
     numerator = 0;
     denominator = 1;
   }

   // possibly other constructors here
  public RN (String str){
	String s1 ,s2 ;
	int slash = str.indexOf("/");
	s1 = str.substring(0,slash);
	s2 = str.substring(slash+1, str.length());	
	numerator = Integer.parseInt(s1);
	denominator = Integer.parseInt(s2);
}




   // you'll definitely need an add method
   public RN add(RN rn) {
	RN result = new RN();
	result.numerator = numerator*rn.denominator + denominator * rn.numerator;
	result.denominator = denominator * rn.denominator;
	return result;
   }

   // for the 100-point version, you'll need subtract and multiply
   public RN subtract(RN rn) {
	RN result = new RN();
	result.numerator = numerator*rn.denominator - denominator * rn.numerator;
	result.denominator = denominator * rn.denominator;
	return result;
   }

   public RN multiply(RN rn) {
	RN result = new RN();
	result.numerator = numerator * rn.numerator;
	result.denominator = denominator * rn.denominator;
	return result;
   }

   // perhaps other methods
   public String toAnswer() {
   //if (denominator == 1 || numerator == 0)
   //    return Integer.toAnswer(numerator);
    // else
       return numerator + "/" + denominator;
  }
}