#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
long long aa[100010];
long long powa(long long a, long long n) {
  long long res = 1;
  while (n) {
    if (n & 1) res = res * a % mod;
    a = a * a % mod;
    n >>= 1;
  }
  return res;
}
int main() {
  int k;
  scanf("%d", &k);
  int t = 0, m = 0;
  for (int i = 0; i < k; i++) {
    scanf("%lld", &aa[i]);
    if (aa[i] > 1) t = 1;
    if (aa[i] % 2 == 0) {
      m = 1;
    }
  }
  if (t == 0) {
    cout << "0/1" << endl;
    return 0;
  }
  long long a = 1, b = 1;
  b = powa(2, aa[0]);
  for (int i = 1; i < k; i++) {
    b = powa(b, aa[i]);
  }
  long long inv2 = powa(2, mod - 2);
  long long inv3 = powa(3, mod - 2);
  b = b * inv2 % mod;
  if (b == 2) {
    cout << "1/2" << endl;
    return 0;
  }
  if (m == 1) {
    a = ((b - 2 + mod) * inv3 % mod + 1) % mod;
  } else
    a = (b - 1 + mod) * inv3 % mod;
  cout << a << "/" << b << endl;
  return 0;
}
