#include <bits/stdc++.h>
using namespace std;
const long long rev_6 = 166666668ll;
const long long rev_2 = 500000004ll;
const long long MOD = 1000000007ll;
long long pow(long long A, long long n) {
  long long r = 1ll;
  while (n) {
    if (n & 1ll) r = r * A % MOD;
    A = A * A % MOD;
    n >>= 1;
  }
  return r;
}
int main() {
  bool odd = true, one = true;
  int k;
  long long ans = 2, temp;
  cin >> k;
  while (k--) {
    cin >> temp;
    if (temp > 1ll) one = false;
    if (temp % 2ll == 0ll) odd = false;
    ans = pow(ans, temp);
  }
  if (one)
    cout << "0/1\n";
  else {
    long long q = ans * rev_2 % MOD;
    if (odd)
      ans -= 2;
    else
      ans += 2;
    if (ans < 0) ans += MOD;
    ans = ans * rev_6 % MOD;
    cout << ans << '/' << q << endl;
  }
}
