#include <bits/stdc++.h>
using namespace std;
int mod = 1000000007;
long long a[100005];
long long pow(int a, int b, int MOD) {
  long long x = 1, y = a;
  while (b > 0) {
    if (b & 1) x = (x * y) % MOD;
    y = (y * y) % MOD;
    b /= 2;
  }
  return x;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int k, i;
  cin >> k;
  bool even = false;
  long long n = 1, p, q;
  for (i = 0; i < k; i++) {
    cin >> a[i];
    if (a[i] % 2 == 0) even = true;
    a[i] %= (mod - 1);
    n = (n * a[i]) % (mod - 1);
  }
  n = ((n - 1) % (mod - 1) + mod - 1) % (mod - 1);
  q = pow(2, n, mod);
  if (even)
    p = (q + 1) % mod;
  else
    p = ((q - 1) % mod + mod) % mod;
  p = (p * pow(3, mod - 2, mod)) % mod;
  cout << p << "/" << q << endl;
}
