#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
long long inv3 = mod / 3 + 1, inv2 = mod / 2 + 1, a, sum, up;
int n;
bool flag;
long long Pow(long long x, long long d) {
  if (d == 0) return 1;
  long long res = Pow(x, d >> 1);
  if (d & 1) return res * res % mod * x % mod;
  return res * res % mod;
}
int main() {
  scanf("%d", &n);
  sum = 2;
  for (int i = 1; i <= n; i++) {
    scanf("%lld", &a);
    sum = Pow(sum, a) % mod;
    if (a % 2 == 0) flag = 1;
  }
  sum = sum * inv2 % mod;
  if (flag)
    up = sum + 1;
  else
    up = sum - 1;
  up = up * inv3 % mod;
  printf("%lld/%lld", up, sum);
  return 0;
}
