problem89.cpp

#include <bits/stdc++.h>
using namespace std;

class AlchemistsFraction {
  string formula;

public:
  void readInput() {
    cin >> formula;
  }

  int gcd(int a, int b) {
    return b == 0 ? a : gcd(b, a % b);
  }

  string solve() {
    int num = 0, den = 1;
    int i = 0, n = formula.size();

    while (i < n) {
      int sign = 1;
      if (formula[i] == '+' || formula[i] == '-') {
        sign = (formula[i] == '+') ? 1 : -1;
        i++;
      }

      int n1 = 0;
      while (i < n && isdigit(formula[i])) {
        n1 = n1 * 10 + (formula[i++] - '0');
      }

      i++; // skip '/'

      int d1 = 0;
      while (i < n && isdigit(formula[i])) {
        d1 = d1 * 10 + (formula[i++] - '0');
      }

      num = num * d1 + sign * n1 * den;
      den = den * d1;

      int g = gcd(abs(num), den);
      num /= g;
      den /= g;
    }

    return to_string(num) + "/" + to_string(den);
  }
};

int main() {
  AlchemistsFraction solver;
  solver.readInput();
  cout << solver.solve() << endl;
  return 0;
}