#include <bits/stdc++.h>
using namespace std;
long long n, ki, a, ki2;
const long long M = 1000000007;
bool paros = false;
long long hatv(long long a, long long b) {
  long long ki = 1, sz = a;
  while (b > 0) {
    if (b % 2) ki = (ki * sz) % M;
    sz = sz * sz % M;
    b /= 2;
  }
  return ki;
}
int main() {
  cin >> n;
  ki = 2;
  for (int i = 0; i < n; i++) {
    cin >> a;
    ki = hatv(ki, a);
    if (a % 2 == 0) paros = true;
  }
  while (ki % 2) ki += M;
  ki = ki / 2;
  ki2 = ki + 1;
  if (!paros) ki2 -= 2;
  while (ki2 % 3) ki2 += M;
  ki2 /= 3;
  ki2 = ki2 % M;
  ki = ki % M;
  cout << ki2 << "/" << ki << endl;
  return 0;
}
