#include <bits/stdc++.h>
using namespace std;
long long int modular_pow(long long int base, long long int exponent,
                          int modulus) {
  long long int result = 1;
  while (exponent > 0) {
    if (exponent % 2 == 1) result = (result * base) % modulus;
    exponent = exponent >> 1;
    base = (base * base) % modulus;
  }
  return result;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int k, p = 1;
  long long int a[100001], ans = 2, dr;
  cin >> k;
  for (int i = 0; i < k; ++i) {
    cin >> a[i];
    if (a[i] % 2 == 0) {
      p = 0;
    }
    ans = modular_pow(ans, a[i], 1000000007);
  }
  long long int inv2 = modular_pow(2, 1000000007 - 2, 1000000007);
  long long int inv3 = modular_pow(3, 1000000007 - 2, 1000000007);
  ans = (ans * inv2) % 1000000007;
  if (p == 0) {
    dr = (ans + 1) % 1000000007;
  } else {
    dr = (ans + 1000000007 - 1) % 1000000007;
  }
  dr = (dr * inv3) % 1000000007;
  cout << dr << '/' << ans;
}
