#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void rd(T &x) {
  x = 0;
  bool check = false;
  register int c;
  do {
    c = getchar();
    if (c == '-') check = true;
  } while (c < 48 || c > 57);
  for (; c < 48 || c > 57; c = getchar())
    ;
  for (; c > 47 && c < 58; c = getchar()) {
    x = (x << 1) + (x << 3) + c - 48;
  }
  if (check) x = -x;
}
template <class T>
inline void pd(T x) {
  char c[21];
  bool check = false;
  int k = -1;
  if (x < 0) check = true, x = -x;
  do {
    c[++k] = x % 10 + 48;
    x /= 10;
  } while (x);
  if (check) c[++k] = '-';
  while (k >= 0) putchar(c[k--]);
  putchar('\n');
}
bool cmp(int a, int b) { return a > b; }
long long int gcd(long long int a, long long int b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
int main() {
  long long int a, b, c, p, q, d, e, ans, cnt, f, g;
  rd(a);
  rd(b);
  rd(c);
  if (b > c) p = b, b = c, c = p;
  d = gcd(b, c);
  f = b / d;
  e = a / f;
  g = a % f;
  g = (g + 1LL * (e % c) * f);
  e = e / c;
  ans = 1LL * b * e;
  ans += min(b - 1, g);
  d = gcd(ans, a);
  p = ans / d;
  q = a / d;
  cout << p << "/" << q << endl;
}
