#include <bits/stdc++.h>
using namespace std;
long long max(long long a, long long b) {
  if (a > b) {
    return a;
  } else {
    return b;
  }
}
long long min(long long a, long long b) {
  if (a < b) {
    return a;
  } else {
    return b;
  }
}
int k;
long long a[600001];
long long bigmod(long long a, long long p) {
  if (!p) return 1;
  long long t = bigmod(a, p >> 1);
  t = t * t % 1000000007;
  if (p & 1) t = (t * (a % 1000000007)) % 1000000007;
  return t;
}
long long rev(long long a) { return bigmod(a, 1000000007 - 2); }
int main() {
  scanf("%d", &k);
  for (int i = (1); i <= (k); i++) cin >> a[i];
  long long base = 2;
  for (int i = (1); i <= (k); i++) base = bigmod(base, a[i]);
  base = (base * rev(2)) % 1000000007;
  long long pd = 1;
  for (int i = (1); i <= (k); i++)
    if (a[i] % 2 == 0) pd = 0;
  long long top;
  if (pd) {
    top = (base - 1 + 1000000007) * rev(3) % 1000000007;
  } else {
    top = (base + 1) % 1000000007 * rev(3) % 1000000007;
  }
  cout << top << "/" << base << endl;
  return 0;
}
