#include <bits/stdc++.h>
using namespace std;
long long hcf(long long x, long long y) {
  if (x == 0) return y;
  return hcf(y % x, x);
}
signed main() {
  long long a, b, c, d, x1, y1, x3, y3, m, n;
  long double k = 0, p = 0;
  cin >> a >> b >> c >> d;
  n = hcf(a, b);
  m = hcf(c, d);
  c /= m;
  d /= m;
  a /= n;
  b /= n;
  if ((a * 1.0) * (d * 1.0) / (c * 1.0) <= (b * 1.0)) {
    k = (a * 1.0) * ((a * 1.0) * (d * 1.0) / (c * 1.0));
    x1 = b * c - a * d;
    y1 = b * c;
  }
  if ((b * 1.0) * (c * 1.0) / (d * 1.0) <= (a * 1.0)) {
    p = (b * 1.0) * ((b * 1.0) * (c * 1.0) / (d * 1.0));
    x3 = a * d - c * b;
    y3 = a * d;
  }
  if (k >= p) {
    m = hcf(x1, y1);
    x1 /= m;
    y1 /= m;
    cout << x1 << "/" << y1;
  } else {
    m = hcf(x3, y3);
    x3 /= m;
    y3 /= m;
    cout << x3 << "/" << y3;
  }
}
