#include <bits/stdc++.h>
using namespace std;
bool is_prime(long long n) {
  long long i;
  for (i = 2; i <= sqrt(n); i++) {
    if (n % i == 0) return false;
  }
  return true;
}
int gcd(int a, int b) {
  if (b == 0)
    return a;
  else
    return gcd(b, a % b);
}
void solve() {
  int a, b, c, d, k;
  cin >> a >> b >> c >> d;
  int num = a * d - b * c;
  int num1 = b * c - a * d;
  if (num > 0) {
    k = gcd(a * d, num);
    cout << num / k << "/" << (a * d) / k << "\n";
    return;
  }
  k = gcd(b * c, num1);
  cout << num1 / k << "/" << (b * c) / k << "\n";
  return;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  solve();
}
