#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
vector<string> vc;
double x, y, z = 0, n = 0, m, sol = 1e10, sz;
int GCD(int a, int b) {
  if (b == 0) return a;
  GCD(b, a % b);
}
int arr[4][3];
int main() {
  int co = 4;
  int a1, b1, a2, b2, c1, c2, d;
  cin >> a1 >> b1 >> a2 >> b2;
  double ras = 1e10;
  int q = 0, w = 1, e = 1;
  for (int i = 0; i < 4; i++) {
    if (i == 3) {
      swap(a1, b1);
      swap(a2, b2);
    }
    x = a1 * b2;
    y = b1 * a2;
    n = x - y;
    m = x;
    c1 = max(n, m);
    c2 = min(n, m);
    d = GCD(c1, c2);
    double r = (n / d) / (m / d);
    if (r < ras && n > 0) {
      ras = r;
      q = n;
      w = d;
      e = m;
    }
    if (i == 3) {
      swap(a1, b1);
      swap(a2, b2);
    }
  }
  cout << q / w << "/" << e / w << endl;
  return 0;
}
