#include <bits/stdc++.h>
using namespace std;
int a, b, c, d;
int gcd(int first, int second) {
  if (!second) return first;
  return gcd(second, first % second);
}
pair<int, int> sol, curr;
int main() {
  cin >> a >> b >> c >> d;
  int dd = gcd(a, b);
  a /= dd;
  b /= dd;
  dd = gcd(c, d);
  c /= dd;
  d /= dd;
  sol.first = 1;
  sol.second = 1;
  if (a * d < b * c) {
    curr.first = (b * c - a * d) * a;
    curr.second = c * a * b;
    dd = gcd(curr.first, curr.second);
    curr.first /= dd;
    curr.second /= dd;
    if (curr.first * sol.second < sol.first * curr.second) sol = curr;
  } else {
    curr.first = (a * d - b * c) * b;
    curr.second = d * a * b;
    dd = gcd(curr.first, curr.second);
    curr.first /= dd;
    curr.second /= dd;
    if (curr.first * sol.second < sol.first * curr.second) sol = curr;
  }
  cout << sol.first << "/" << sol.second << "\n";
  return 0;
}
