#include <bits/stdc++.h>
using namespace std;
const int MD = (int)1e9 + 7;
long long mul(long long a, long long b) { return (a * b) % MD; }
long long pot(long long a, long long b) {
  long long res = 1;
  for (; b; b >>= 1) {
    if (b & 1) {
      res = mul(res, a);
    }
    a = mul(a, a);
  }
  return res;
}
long long inv(long long x) { return pot(x, MD - 2); }
int main() {
  int k;
  cin >> k;
  bool even_n = true;
  long long q = 2;
  while (k--) {
    long long a;
    cin >> a;
    q = pot(q, a);
    if (a % 2 == 0) {
      even_n = false;
    }
  }
  q = mul(q, inv(2));
  long long p;
  if (even_n) {
    p = (q - 1) % MD;
  } else {
    p = (q + 1) % MD;
  }
  p = mul(p, inv(3));
  cout << p << "/" << q << endl;
}
