#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() {
  int a, b, c, d;
  scanf("%d%d%d%d", &a, &b, &c, &d);
  if (a < b) {
    if (c < d) {
      if (d * a > b * c)
        printf("%d/%d\n", (a * d - b * c) / gcd(a * d - b * c, a * d),
               a * d / gcd(a * d - b * c, a * d));
      else
        printf("%d/%d\n", (b * c - a * d) / gcd(b * c - a * d, b * c),
               b * c / gcd(b * c - a * d, b * c));
    } else {
      printf("%d/%d\n", (b * c - a * d) / gcd(b * c - a * d, b * c),
             b * c / gcd(b * c - a * d, b * c));
    }
  } else {
    if (c < d) {
      printf("%d/%d\n", (a * d - b * c) / gcd(a * d - b * c, a * d),
             a * d / gcd(a * d - b * c, a * d));
      ;
    } else {
      if (d * a > b * c)
        printf("%d/%d\n", (a * d - b * c) / gcd(a * d - b * c, a * d),
               a * d / gcd(a * d - b * c, a * d));
      else
        printf("%d/%d\n", (b * c - a * d) / gcd(b * c - a * d, b * c),
               b * c / gcd(b * c - a * d, b * c));
    }
  }
  return 0;
}
