import java.util.Scanner;
public class Laba2_2 {
    final static Scanner scan = new Scanner(System.in);
    final static int MAX_VALUE = 100;
    static int inputNumber(){
        boolean isIncorrect;
        int number = 0;
        do{
            isIncorrect = false;
            try {
                number = Integer.parseInt(scan.nextLine());
            }
            catch (NumberFormatException e) {
                System.err.println("Введите натуральное число!");
                isIncorrect = true;
            }
            if (!isIncorrect && (number < 1 || number > MAX_VALUE)) {
                System.err.println("Введите число в диапахоне от 1 до 100");
                isIncorrect = true;
            }
        } while (isIncorrect);
        return number;
    }
    static int findNOD(int firstNumber, int secondNumber){
        while (secondNumber != 0) {
            if (firstNumber > secondNumber)
                firstNumber = firstNumber - secondNumber;
            else
                secondNumber = secondNumber - firstNumber;
        }
        return firstNumber;
    }
    static int findNOK(int firstNumber, int secondNumber){
        int nod = findNOD(firstNumber, secondNumber);
        int nok = (firstNumber * secondNumber) / nod;
        return nok;
    }
    static boolean checkDivisors(int numerator, int denominator){
        int divisors;
        divisors = findNOD(numerator, denominator);
        if (divisors > 1) {
            System.out.println("Дробь должна быть несократимой!");
            return false;
        }
        return true;
    }
    static void fixIfDivisorsFind(int[] fraction){
        while(!checkDivisors(fraction[0], fraction[1])){
            System.out.println("Введите числитель дроби");
            fraction[0] = inputNumber();
            System.out.println("Введите знаменатель дроби");
            fraction[1] = inputNumber();
        }
    }
    static int takeDenominator(int n, int q){
        int denominator = findNOK(n, q);
        return denominator;
    }
    static int takeNumerator(int denominator, int m, int n, int p, int q){
        int numerator = (denominator / n * m) + (denominator / q * p);
        return numerator;
    }
    static int[] cutFraction(int numerator, int denominator){
        int nod = findNOD(numerator, denominator);
        int finalNumerator = numerator / nod;
        int finalDenominator = denominator / nod;
        int[] arr = {finalNumerator, finalDenominator};
        return arr;
    }
    static void outputFraction(int[] arr){
        System.out.println("Сумма дробей: " + arr[0] + "/" + arr[1]);
    }
    public static void main(String[] args) {
        System.out.println("Программа считает сумму двух обыкновенных несократимых дробей");
        int m;
        int n;
        System.out.println("Введите числитель первой дроби");
        m = inputNumber();
        System.out.println("Введите знаменатель первой дроби");
        n = inputNumber();
        int[] firstFraction = {m, n};
        fixIfDivisorsFind(firstFraction);
        int p;
        int q;
        System.out.println("Введите числитель второй дроби");
        p = inputNumber();
        System.out.println("Введите знаменатель второй дроби");
        q = inputNumber();
        int[] secondFraction = {p, q};
        fixIfDivisorsFind(secondFraction);
        scan.close();
        int denominator;
        int numerator;
        denominator = takeDenominator(firstFraction[1], secondFraction[1]);
        numerator = takeNumerator(denominator, firstFraction[0], firstFraction[1], secondFraction[0], secondFraction[1]);
        int[] arr = cutFraction(numerator, denominator);
        outputFraction(arr);
    }
}