#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 10;
const int mod = 1e9 + 7;
long long num;
long long pow_mod(long long a, long long b, long long m) {
  long long ret = 1;
  a %= m;
  while (b > 0) {
    if (b % 2 == 1) ret = (ret * a) % m;
    a = a * a % m;
    b >>= 1;
  }
  return ret;
}
int main() {
  int n;
  cin >> n;
  long long b = 2, flag = -1;
  for (int i = 0; i < n; i++) {
    cin >> num;
    b = pow_mod(b, num, mod);
    if (num % 2 == 0) flag = 1;
  }
  b = b * pow_mod(2LL, mod - 2, mod) % mod;
  long long a = (b + flag + mod) % mod * pow_mod(3LL, mod - 2, mod) % mod;
  cout << a << "/" << b << endl;
  return 0;
}
