#include <bits/stdc++.h>
using namespace std;
int main(int argc, char const *argv[]) {
  bool is_even = false;
  const long long p_1 = 1000000006;
  const long long p = 1000000007;
  const long long two_inv = 500000004;
  const long long three_inv = 333333336;
  long long k, temp, a = 1, answer = 1;
  cin >> k;
  for (long long i = 0; i < k; ++i) {
    cin >> temp;
    if (temp % 2 == 0) is_even = true;
    temp %= p_1;
    a *= temp;
    a %= p_1;
  }
  temp = 2;
  while (a != 0) {
    if (a % 2 == 1) answer *= temp;
    answer %= p;
    temp *= temp;
    temp %= p;
    a /= 2;
  }
  answer *= two_inv;
  answer %= p;
  if (is_even)
    cout << (((answer + 1) * three_inv) % p);
  else
    cout << (((answer - 1) * three_inv) % p);
  cout << "/" << (answer);
  return 0;
}
