#include <bits/stdc++.h>
using namespace std;
const int Mod = 1e9 + 7;
long long Pow(long long a, long long n, long long mod) {
  long long t = 1;
  for (; n; n >>= 1, a = (a * a % mod))
    if (n & 1) t = (t * a % mod);
  return t;
}
int main() {
  int k;
  long long tmp, n;
  while (scanf("%d", &k) == 1) {
    n = 1;
    int flag = 0;
    for (int i = 0; i < k; i++) {
      scanf("%lld", &tmp);
      n = n * (tmp % (Mod - 1)) % (Mod - 1);
    }
    long long p =
        (Pow(2, (n - 1 + Mod - 1) % (Mod - 1), Mod) + Pow(-1, n, Mod)) % Mod *
        Pow(3, Mod - 2, Mod) % Mod;
    long long q = Pow(2, (n - 1 + Mod - 1) % (Mod - 1), Mod);
    printf("%lld/%lld\n", p, q);
  }
  return 0;
}
