#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
vector<vector<long long>> mul(vector<vector<long long>> a,
                              vector<vector<long long>> b) {
  vector<vector<long long>> c;
  for (int i = 0; i < a.size(); i++) {
    c.push_back({});
    for (int j = 0; j < b[0].size(); j++) {
      c[i].push_back(0);
      for (int k = 0; k < a[0].size(); k++) {
        c[i].back() = (c[i].back() + a[i][k] * b[k][j]) % mod;
      }
    }
  }
  return c;
}
int main() {
  ios::sync_with_stdio(false);
  mt19937 rng(328);
  int n;
  long long k, c = 1, d = 1, e = 2;
  vector<vector<long long>> a = {{1, 0}, {0, 1}}, b = {{0, 1}, {2, 1}};
  cin >> n;
  while (n--) {
    cin >> k;
    c = (c * (k % (mod - 1))) % (mod - 1);
  }
  while (c) {
    if (c & 1) a = mul(a, b), d = d * e % mod;
    b = mul(b, b);
    e = e * e % mod;
    c >>= 1;
  }
  cout << a[0][0] * 500000004 % mod << '/' << d * 500000004 % mod << '\n';
}
