#include <bits/stdc++.h>
using namespace std;
long long int power(long long int a, long long int b) {
  a = a % 1000000007;
  long long int val = 1;
  while (b) {
    if (b % 2) val = (val * a) % 1000000007;
    a = (a * a) % 1000000007;
    b /= 2;
  }
  return val;
}
long long int divide(long long int a, long long int b) {
  return (a * power(b, 1000000007 - 2)) % 1000000007;
}
int main() {
  long long int n, i, val = 1;
  cin >> n;
  long long int a[n];
  val = 2;
  bool flag = false;
  for (i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] % 2 == 0) flag = true;
    val = power(val, a[i]);
  }
  val = divide(val, 2ll);
  long long int p = val, q = val;
  if (flag == false)
    p = divide(p - 1, 3);
  else {
    p = divide(p + 1, 3);
  }
  if (p == 0) {
    cout << "0/1" << endl;
    return 0;
  }
  cout << p << "/" << q << endl;
  return 0;
}
