#include <iostream>
#include <string>;
using namespace std;
const int MAX_VALUE = 100;
int checkException(int number) {
    bool isIncorrect;
    number = 0;
    do{
        cin >> number;
        isIncorrect = false;
        if (cin.fail() || number < 1){
            cin.clear();
            cin.ignore(1000, '\n');
            cout << "Введите натуральное число!\n";
            isIncorrect = true;
        }
        if (number < 1 || number > MAX_VALUE) {
            cout << "Введите число в диапахоне от 1 до 100\n";
        }
    } while (isIncorrect);
    return number;
}
int inputNumber(string text) {
    int number = 0;
    cout << "Введите " + text + " дроби: ";
    number = checkException(number);
    return number;
}
int findNOD(int firstNumber, int secondNumber) {
    while (secondNumber != 0) {
        if (firstNumber > secondNumber)
            firstNumber = firstNumber - secondNumber;
        else
            secondNumber = secondNumber - firstNumber;
    }
    return firstNumber;
}
int findNOK(int firstNumber, int secondNumber) {
    int nod = findNOD(firstNumber, secondNumber);
    int nok = (firstNumber * secondNumber) / nod;
    return nok;
}
void checkDivisors(int numerator, int denominator) {
    int divisors;
    bool isIncorrect;
    do {
        isIncorrect = false;
        divisors = findNOD(numerator, denominator);
        if (divisors > 1) {
            cout << "Дробь должна быть несократимой!\n";
            numerator = inputNumber("числитель");
            denominator = inputNumber("знаменатель");
            isIncorrect = true;
        }
    } while (isIncorrect);
}
int takeDenominator(int firstDenominator, int secondDenominator) {
    int denominator = findNOK(firstDenominator, secondDenominator);
    return denominator;
}
int takeNumerator(int denominator, int m, int n, int p, int q) {
    int numerator = (denominator / n * m) + (denominator / q * p);
    return numerator;
}
void cutFraction(int* numerator, int* denominator) {
    int nod = findNOD(*numerator, *denominator);
    *numerator = *numerator / nod;
    *denominator = *denominator / nod;
}
string takeFraction(int numerator, int denominator) {
    string result = to_string(numerator) + "/" + to_string(denominator);
    return result;
}
void outputFraction(int numerator, int denominator) {
    cout << "Сумма дробей: " << numerator << "/" << denominator;
}
int main() {
    system("chcp 1251");
    system("cls");
    cout << "Программа считает сумму двух обыкновенных несократимых дробей\n";
    int firstNumerator;
    int firstDenominator;
    firstNumerator = inputNumber("числитель первой");
    firstDenominator = inputNumber("знаменатель первой");
    checkDivisors(firstNumerator, firstDenominator);
    int secondNumerator;
    int secondDenominator;
    secondNumerator = inputNumber("числитель второй");
    secondDenominator = inputNumber("знаменатель второй");
    checkDivisors(secondNumerator, secondDenominator);
    int denominator;
    int numerator;
    denominator = takeDenominator(firstDenominator, secondDenominator);
    numerator = takeNumerator(denominator, firstNumerator, firstDenominator, secondNumerator, secondDenominator);
    cutFraction(&numerator, &denominator);
    outputFraction(numerator, denominator);
    return 0;
}