#include <bits/stdc++.h>
using namespace std;
int gcd(int a, int b) { return (a % b == 0) ? b : gcd(b, a % b); }
pair<int, int> mul(pair<int, int> a, pair<int, int> b) {
  pair<int, int> res = make_pair(
      (a.first * b.first) / gcd((a.first * b.first), (a.second * b.second)),
      (a.second * b.second) / gcd((a.first * b.first), (a.second * b.second)));
  return res;
}
pair<int, int> sub(pair<int, int> a, pair<int, int> b) {
  pair<int, int> res;
  if (a.first * b.second - a.second * b.first > 0) {
    res = make_pair(
        (a.first * b.second - a.second * b.first) /
            gcd((a.first * b.second - a.second * b.first),
                (a.second * b.second)),
        (a.second * b.second) / gcd((a.first * b.second - a.second * b.first),
                                    (a.second * b.second)));
  } else {
    res = make_pair(
        (a.first * b.second - a.second * b.first) /
            gcd((-a.first * b.second + a.second * b.first),
                (a.second * b.second)),
        (a.second * b.second) / gcd((-a.first * b.second + a.second * b.first),
                                    (a.second * b.second)));
  }
  return res;
}
int main() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  int gcc = gcd(c, d), gca = gcd(a, b);
  a = a / gca;
  b = b / gca;
  c = c / gcc;
  d = d / gcc;
  pair<int, int> a1, b1, c1, d1, cbyd, dbyc, one, byb, bya;
  a1 = make_pair(a, 1);
  bya = make_pair(1, a);
  b1 = make_pair(b, 1);
  byb = make_pair(1, b);
  c1 = make_pair(c, 1);
  d1 = make_pair(d, 1);
  cbyd = make_pair(c, d);
  dbyc = make_pair(d, c);
  one = make_pair(1, 1);
  pair<int, int> res;
  pair<int, int> sub1 = sub(b1, mul(a1, dbyc));
  if (sub(b1, mul(a1, dbyc)).first > 0) {
    res = mul(sub(b1, mul(a1, dbyc)), byb);
    cout << res.first / gcd(res.first, res.second) << "/"
         << res.second / gcd(res.first, res.second);
  } else {
    res = mul(sub(a1, mul(b1, cbyd)), bya);
    cout << res.first / gcd(res.first, res.second) << "/"
         << res.second / gcd(res.first, res.second);
  }
}
