#include <bits/stdc++.h>
using namespace std;
long long mod = 1e9 + 7;
long long poww(long long a, long long x) {
  long long ans = 1;
  while (x) {
    if (x & 1) ans = (ans * a) % mod;
    x >>= 1;
    a = (a * a) % mod;
  }
  return ans;
}
long long n, p, t = 2, f = 0;
int main() {
  cin >> n;
  for (int i = 1; i <= n; ++i) {
    cin >> p;
    t = poww(t, p);
    f |= (p % 2 == 0);
  }
  t = t * (mod / 2 + 1) % mod;
  if (f) {
    f = ((t + 1) * (mod / 3 + 1) % mod + mod) % mod;
  } else {
    f = ((t - 1) * (mod / 3 + 1) % mod + mod) % mod;
  }
  cout << f << '/' << t << endl;
}
