#include <bits/stdc++.h>
using namespace std;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
const int N = 200005;
const int M = 1000000007;
long long ast(long long x, long long n) {
  x %= M;
  long long ans = 1;
  while (n) {
    if (n % 2 == 1) ans = (ans * x) % M;
    x = (x * x) % M;
    n /= 2;
  }
  return ans;
}
int n;
long long a[N];
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; ++i) scanf("%lld", &a[i]);
  long long u = 2;
  long long k = 1;
  for (int i = 1; i <= n; ++i) {
    u = ast(u, a[i]);
    if (a[i] % 2 == 0) k = 0;
  }
  u = (u * ast(2, M - 2)) % M;
  long long x;
  if (k == 0)
    x = ((u + 1) * ast(3, M - 2)) % M;
  else
    x = ((u - 1 + M) % M * ast(3, M - 2)) % M;
  printf("%lld/%lld\n", x, u);
  return 0;
}
