#include <bits/stdc++.h>
using namespace std;
const long long MAXN = 1e6;
long long a[MAXN], mod = 1e9 + 7, ans;
long long power(long long x, long long y) {
  if (y == 0) return 1;
  long long mid = power(x, y / 2);
  if (y % 2 == 1)
    return mid * mid % mod * x % mod;
  else
    return mid * mid % mod;
}
int main() {
  int n;
  cin >> n;
  bool is = false, is2 = false;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] % 2 == 0) is = true;
    if (a[i] != 1) is2 = true;
  }
  for (int i = 0; i < n; i++) {
    if (i == 0)
      ans = power(2, a[i]);
    else
      ans = power(ans, a[i]);
  }
  ans = ans * power(2, mod - 2) % mod;
  long long ans2 = ans;
  long long k = -1;
  if (is) k = 1;
  ans = (ans + k) * power(3, mod - 2) % mod;
  cout << ans << '/' << ans2 << endl;
  return 0;
}
