#include <bits/stdc++.h>
using namespace std;
long long power(long long a, long long b, long long m) {
  long long res = 1;
  while (b != 0) {
    if (b % 2) {
      res = (res * a) % m;
    }
    a = (a * a) % m;
    b = b >> 1;
  }
  return res;
}
int main() {
  long long k;
  long long i, j, n;
  n = 1;
  cin >> k;
  long long f = 0;
  long long ans;
  for (i = 0; i < k; i++) {
    long long a;
    cin >> a;
    if (a % 2 == 0) f = 1;
    a = a % (1000000007 - 1);
    n = (n * a) % (1000000007 - 1);
  }
  n = (n + 1000000007 - 2) % (1000000007 - 1);
  if (f == 1) {
    ans = (((1 + power(2, n, 1000000007)) % 1000000007) *
           power(3, 1000000007 - 2, 1000000007)) %
          1000000007;
  } else {
    ans = (((power(2, n, 1000000007) - 1 + 1000000007) % 1000000007) *
           power(3, 1000000007 - 2, 1000000007)) %
          1000000007;
  }
  cout << ans << "/" << power(2, n, 1000000007) << endl;
  return 0;
}
