#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
long long BM(long long b, long long p) {
  long long ret = 1;
  while (p) {
    if (p & 1) ret = (ret * b) % mod;
    b = (b * b) % mod;
    p >>= 1LL;
  }
  return ret;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(nullptr);
  int k;
  long long n = 1, a, p = 1, q = 1, m = 1;
  cin >> k;
  for (int i = 0; i < k; i++) {
    cin >> a;
    n *= a;
    n &= 1;
    m *= (a % (mod - 1));
    m %= (mod - 1);
  }
  m--;
  m %= (mod - 1);
  m += (mod - 1);
  m %= (mod - 1);
  p = (p * BM(2, m)) % mod;
  q = (q * BM(2, m)) % mod;
  if (n & 1)
    p--;
  else
    p++;
  p %= mod;
  p += mod;
  p %= mod;
  p *= BM(3, mod - 2);
  p %= mod;
  cout << p << "/" << q << "\n";
  return 0;
}
