#include <bits/stdc++.h>
int main() {
  int i, a, b, c, d, big, lcm;
  scanf("%d %d %d %d", &a, &b, &c, &d);
  if (((float)(a)) / ((float)(b)) >= ((float)(c)) / ((float)(d))) {
    if (b < d)
      big = d;
    else
      big = b;
    for (i = big;; i += big) {
      if (i % b == 0 && i % d == 0) {
        lcm = i;
        break;
      }
    }
    a *= (lcm / b);
    c *= (lcm / d);
    b = lcm;
    d = lcm;
    for (i = c; i >= 2; i--) {
      if (a % i == 0 && c % i == 0) {
        a /= i;
        c /= i;
      }
    }
    printf("%d/%d \n", a - c, a);
  } else if (((float)(a)) / ((float)(b)) < ((float)(c)) / ((float)(d))) {
    if (a < c)
      big = c;
    else
      big = a;
    for (i = big;; i += big) {
      if (i % a == 0 && i % c == 0) {
        lcm = i;
        break;
      }
    }
    b *= (lcm / a);
    d *= (lcm / c);
    a = lcm;
    c = lcm;
    for (i = d; i >= 2; i--) {
      if (b % i == 0 && d % i == 0) {
        b /= i;
        d /= i;
      }
    }
    printf("%d/%d\n", b - d, b);
  }
  return 0;
}
