#include <bits/stdc++.h>
using namespace std;
int gcd(int x, int y) {
  if (y == 0) {
    return x;
  }
  return gcd(y, x % y);
}
void solve(int &x, int &y) {
  int z = gcd(x, y);
  while (z != 1) {
    x = x / z;
    y = y / z;
    z = gcd(x, y);
  }
  cout << x << "/" << y;
}
int main() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  if (float(a) / float(b) > float(c) / float(d)) {
    int x = a * d - b * c, y = a * d;
    solve(x, y);
  }
  if (float(a) / float(b) < float(c) / float(d)) {
    int x = b * c - a * d, y = b * c;
    solve(x, y);
  }
  if (float(a) / float(b) == float(c) / float(d)) {
    cout << "0/1";
  }
}
