#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1000000000 + 7;
long long my_pow(long long a, long long n) {
  if (n == 0) return 1;
  long long x = my_pow((a * a) % MOD, n / 2);
  if (n & 1) x = (x * a) % MOD;
  return x;
}
int main() {
  int n;
  cin >> n;
  long long first = 2;
  bool even = false;
  bool deducted = false;
  while (n--) {
    long long t;
    cin >> t;
    if (!deducted && t > 1) {
      deducted = true;
    }
    first = my_pow(first, t);
    if (t % 2 == 0) even = true;
  }
  if (!deducted) {
    cout << "0/1" << endl;
    return 0;
  }
  first = (first * my_pow(2, MOD - 2)) % MOD;
  long long second = first;
  first = (MOD + first - (!even ? 1 : -1)) % MOD;
  first = (first * my_pow(3, MOD - 2)) % MOD;
  cout << first << "/" << second << endl;
  return 0;
}
