#include <bits/stdc++.h>
using namespace std;
const long long int M = 1e9 + 7;
const long long int Inv2 = 500000004;
const long long int Inv3 = 333333336;
long long int Pow(long long int x, long long int p) {
  if (p == 0) return 1;
  if (p == 1) return x % M;
  long long int r = Pow(x, p / 2);
  r = (r * r) % M;
  return (r * Pow(x, p % 2)) % M;
}
int main() {
  long long int k;
  cin >> k;
  long long int a[112345];
  long long int x = 2;
  long long int z = 1;
  for (int i = 1; i <= k; i++) {
    cin >> a[i];
    z = (z) & (a[i] % 2);
    x = Pow(x, a[i]) % M;
  }
  z ^= 1;
  if (z == 0) {
    x = (x * Inv2) % M;
    long long int m = x;
    long long int s = (((x - 1 + M) % M) * Inv3) % M;
    cout << s << "/" << m << "\n";
  } else {
    x = (x * Inv2) % M;
    long long int m = x;
    long long int s = (x * Inv2) % M;
    s = (s - 1 + M) % M;
    s = (s * 2) % M;
    s = (s * Inv3) % M;
    s = (s + 1) % M;
    cout << s << "/" << m << "\n";
  }
  return 0;
}
