#include <bits/stdc++.h>
using namespace std;
void debug() { cout << endl; }
template <typename T, typename... Args>
void debug(T a, Args... args) {
  cout << a << ' ';
  debug(args...);
}
const int MOD = 1e9 + 7;
long long mulmod(long long a, long long b, long long m) {
  long long r = a * b - (long long)((long double)a * b / m + .5) * m;
  return r < 0 ? r + m : r;
}
long long expmod(long long b, long long e, long long m) {
  if (e == 0) return 1;
  if (e & 1) return mulmod(b, expmod(b, e - 1, m), m);
  b = expmod(b, e >> 1, m);
  return mulmod(b, b, m);
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int k, xp = 1;
  cin >> k;
  bool par = false;
  for (int i = 0, gon = k; i < gon; ++i) {
    long long n;
    cin >> n;
    par |= !(n & 1);
    xp = mulmod(n % (MOD - 1), xp, MOD - 1);
  }
  xp = (xp - 1 + (MOD - 1)) % (MOD - 1);
  int num, den;
  num = den = expmod(2, xp, MOD);
  if (par)
    num = (num + 1) % MOD;
  else
    num = (num - 1 + MOD) % MOD;
  int inv = expmod(3, MOD - 2, MOD);
  num = mulmod(num, inv, MOD);
  cout << num << "/" << den << '\n';
}
