#include <bits/stdc++.h>
using namespace std;
long long int k, a[100002];
long long int mod_pow(long long int base, long long int exp) {
  long long int ret = 1;
  while (exp) {
    if (exp % 2) ret = (ret * base) % 1000000007;
    exp = exp >> 1;
    base = (base * base) % 1000000007;
  }
  return ret;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> k;
  long long int c1 = 0, c2 = 0;
  for (long long int i = 1; i <= k; ++i) {
    cin >> a[i];
    if (a[i] == 1) c1++;
    if (a[i] % 2 == 0) c2++;
  }
  if (c1 == k) {
    cout << "0/1\n";
    return 0;
  }
  long long int ans = 2LL;
  for (long long int i = 1; i <= k; ++i) {
    ans = mod_pow(ans, a[i]);
  }
  ans = (ans * mod_pow(2LL, 1000000007 - 2)) % 1000000007;
  if (c2) {
    long long int num =
        (((ans + 1) % 1000000007) * mod_pow(3LL, 1000000007 - 2)) % 1000000007;
    cout << num << "/" << ans << endl;
    return 0;
  }
  long long int num = ((((ans - 1) % 1000000007 + 1000000007)) % 1000000007 *
                       mod_pow(3LL, 1000000007 - 2)) %
                      1000000007;
  cout << num << "/" << ans << endl;
}
