#include <bits/stdc++.h>
using namespace std;
long long power(int a, int b) {
  if (b == 0) return 1;
  long long v = power(a, b / 2);
  if (b % 2 == 1) {
    long long cast = (long long)a;
    return (cast * (v * v) % 1000000007) % 1000000007;
  }
  return (v * v) % 1000000007;
}
int main() {
  int k;
  cin >> k;
  long long expo = 1, pot;
  int unit = -1;
  for (int i = 1; i <= k; i++) {
    long long a;
    cin >> a;
    if (a % 2 == 0) unit = 1;
    if (a == 0) {
      cout << "0/1";
      return 0;
    }
    a = a % 500000003;
    expo *= a;
    expo = expo % 500000003;
  }
  pot = power(2, expo);
  pot = (pot * 500000004) % 1000000007;
  long long p = (pot + unit) * 333333336;
  p = p % 1000000007;
  cout << p << "/" << pot;
  return 0;
}
