#include <bits/stdc++.h>
using namespace std;
void gett() { cerr << (clock()) / (double)CLOCKS_PER_SEC << "\n"; }
long long powr(long long a, long long b, long long mod) {
  long long x = 1 % mod;
  a %= mod;
  while (b) {
    if (b & 1) x = (x * a) % mod;
    a = (a * a) % mod;
    b >>= 1;
  }
  return x;
}
long long inv(long long a, long long mod) { return powr(a, mod - 2, mod); }
const int maxn = 1e6 + 10;
const long long mod = 1e9 + 7;
long long a[maxn];
int main() {
  int k;
  cin >> k;
  int n = k;
  bool even = 0;
  for (__typeof(k) i = (0) - ((0) > (k)); i != (k) - ((0) > (k)); i += 1) {
    scanf("%lld", &(a[i]));
    if (!(a[i] & 1)) even = 1;
  }
  long long den = 2;
  for (__typeof(n) i = (0) - ((0) > (n)); i != (n) - ((0) > (n)); i += 1) {
    den = powr(den, a[i], mod);
  }
  den = (den * inv(2, mod)) % mod;
  long long den1 = den;
  if (even) {
    den = (den + 1) % mod;
  } else {
    den = ((den - 1) % mod + mod) % mod;
  }
  den = (den * inv(3, mod)) % mod;
  cout << den << "/" << den1;
}
