#include <bits/stdc++.h>
using namespace std;
long long int modularexpo(long long int base, long long int exp) {
  long long int ans = 1;
  while (exp) {
    if (exp % 2) ans = (ans * base) % 1000000007;
    exp /= 2;
    base = (base * base) % 1000000007;
  }
  return ans;
}
int main() {
  long long int p, q, k, i, flag, num, temp;
  cin >> k;
  flag = 1;
  temp = 1;
  for (i = 0; i < k; i++) {
    cin >> num;
    if (num % 2 == 0) flag = 0;
    num %= (1000000007 - 1);
    temp = (temp * num) % (1000000007 - 1);
  }
  temp = (temp - 1) % (1000000007 - 1);
  if (temp < 0) temp += (1000000007 - 1);
  q = modularexpo(2, temp);
  if (flag) {
    p = (q - 1) % 1000000007;
    if (p < 0) p += 1000000007;
  } else
    p = (q + 1) % 1000000007;
  p = (p * modularexpo(3, 1000000007 - 2)) % 1000000007;
  cout << p << "/" << q;
  return 0;
}
