#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const long long LINF = 0x3f3f3f3f3f3f3f3fll;
long long modpower(long long a, unsigned long long p, long long MOD) {
  long long r = 1;
  while (p) {
    if (p & 1) r = (r * a) % MOD;
    a = (a * a) % MOD;
    p >>= 1;
  }
  return r;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int k;
  cin >> k;
  vector<long long> a(k);
  for (int i = 0; i < (int)a.size(); ++i) cin >> a[i];
  ;
  const long long MOD = 1e9 + 7;
  long long n = 1, r = 1;
  for (int i = 0; i < k; ++i) {
    n = (n * (a[i] % (MOD - 1))) % (MOD - 1);
    r = min(r, a[i] % 2);
  }
  n = (n - 1 + MOD - 1) % (MOD - 1);
  long long q = modpower(2, n, MOD);
  long long p = (q + (r ? -1 : 1) + MOD) % MOD;
  p = (p * modpower(3, MOD - 2, MOD)) % MOD;
  cout << p << "/" << q << '\n';
  exit(0);
}
