#include <bits/stdc++.h>
using namespace std;
int gcd(int a, int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
int main() {
  FILE *fp, *fo;
  fp = fopen("input.txt", "r");
  fo = fopen("output.txt", "w");
  int a, b, c, d, ans, p1, p2, p3, p4, p5, p11, p22, p33, p44, p55, check1,
      check2, lcmp, lcmac, lcmbd;
  scanf("%d", &a);
  scanf("%d", &b);
  scanf("%d", &c);
  scanf("%d", &d);
  lcmac = (a * c) / gcd(a, c);
  lcmbd = (b * d) / gcd(b, d);
  p1 = (lcmac / a) * b;
  p2 = (lcmac / c) * d;
  p3 = abs(p1 - p2);
  p4 = max(p1, p2);
  p11 = (lcmbd / b) * a;
  p22 = (lcmbd / d) * c;
  p33 = abs(p11 - p22);
  p44 = max(p11, p22);
  lcmp = (p44 * p4) / gcd(p44, p4);
  check1 = (p3) * (lcmp / p4);
  check2 = (p33) * (lcmp / p44);
  if (check1 < check2) {
    p5 = gcd(p3, p4);
    p3 = p3 / p5;
    p4 = p4 / p5;
    cout << p3 << "/" << p4 << endl;
  } else {
    p5 = gcd(p33, p44);
    p33 = p33 / p5;
    p44 = p44 / p5;
    cout << p33 << "/" << p44 << endl;
  }
  return 0;
}
