#include <bits/stdc++.h>
using namespace std;
unsigned long long avoidOverflowMul(unsigned long long x,
                                    unsigned long long y) {
  unsigned long long ret = x;
  unsigned long long div4ret = y >> 4;
  unsigned long long restret = y % 16;
  unsigned long long temp = (ret * div4ret) % 6000000042;
  temp = (temp * 16) % 6000000042;
  ret = (temp + ret * restret) % 6000000042;
  return ret;
}
unsigned long long pow(unsigned long long x, unsigned long long y) {
  if (y == 1) return x;
  unsigned long long ret = pow(x, y >> 1);
  ret = avoidOverflowMul(ret, ret);
  if (y % 2 == 1) ret = avoidOverflowMul(ret, x);
  return ret;
}
int n;
int main() {
  std::ios::sync_with_stdio(false);
  cin >> n;
  unsigned long long check = 1;
  unsigned long long temp;
  unsigned long long two = 2;
  for (int i = 0; i < n; ++i) {
    cin >> temp;
    two = pow(two, temp);
    if (check <= 1) check *= temp;
  }
  if (check == 1) {
    cout << "0/1" << endl;
  } else {
    cout << ((two + 2) / 6) << "/" << ((two % 2000000014) / 2) << endl;
  }
  return 0;
}
