#include <bits/stdc++.h>
using namespace std;
int64_t GCD(int64_t a, int64_t b) {
  if (b == 0) return a;
  return GCD(b, a % b);
}
int64_t LCM(int64_t a, int64_t b) { return b * a / GCD(a, b); }
int main() {
  int64_t a, b, c, d;
  cin >> a >> b >> c >> d;
  if ((float)a / (float)b > (float)c / (float)d) {
    int64_t y = LCM(b, d);
    int64_t mul1 = y / b;
    int64_t mul2 = y / d;
    int64_t _a, _b, _c, _d;
    _a = mul1 * a;
    _b = mul1 * b;
    _c = mul2 * c;
    _d = mul2 * d;
    int64_t area1 = _a * _b;
    int64_t area2 = _c * _d;
    int64_t newNumber1 = area1 / GCD(area1, area2);
    int64_t newNumber2 = area2 / GCD(area1, area2);
    cout << newNumber1 - newNumber2 << "/" << newNumber1 << endl;
  } else {
    int64_t y = LCM(a, c);
    int64_t mul1 = y / a;
    int64_t mul2 = y / c;
    int64_t _a, _b, _c, _d;
    _a = mul1 * a;
    _b = mul1 * b;
    _c = mul2 * c;
    _d = mul2 * d;
    int64_t area1 = _a * _b;
    int64_t area2 = _c * _d;
    int64_t newNumber1 = area1 / GCD(area1, area2);
    int64_t newNumber2 = area2 / GCD(area1, area2);
    cout << newNumber1 - newNumber2 << "/" << newNumber1 << endl;
  }
  return 0;
}
