#include <iostream>
#include <vector>

using std::vector;
using std::cin;

const long long MOD = 1e9 + 7;

long long power(long long x, long long p) {
  long long res = 1;
  long long x_in_pow = x;
  while (p) {
    if (p & 1) {
      res = (x_in_pow * res) % MOD;
    }

    x_in_pow = (x_in_pow * x_in_pow) % MOD;
    p >>= 1;
  }

  return res;
}

int main() {
  long long k;
  cin >> k;

  long long res = 2;
  long long sign = -1;

  vector<long long> arr(k);
  for (long long i = 0; i < k; ++i) {
    cin >> arr[i];
    res = power(res, arr[i]);
    if (sign == -1) {
      sign = (arr[i] % 2 ? -1 : 1);
    }
  }

  // std::cout << (MOD + 1) / 3 << "\n";
  res = (res * 500'000'004LL) % MOD;
  long long num = res + sign;
  num = (num * 333'333'336LL) % MOD;

  std::cout << num << "/" << res;
  return 0;
}