#include <bits/stdc++.h>
using namespace std;
long long int pp(long long int a, long long b) {
  long long int ans = 1;
  while (b) {
    if (b & 1LL) ans = (ans * a) % 1000000007;
    a = (a * a) % 1000000007;
    b = b >> 1;
  }
  return ans;
}
int main() {
  long long int n, x = 2, k = 0, t = 0;
  cin >> n;
  while (n--) {
    cin >> k;
    if (!(k & 1LL)) t = 1;
    x = pp(x, k);
  }
  x = (x * pp(2, 1000000007 - 2)) % 1000000007;
  if (t == 0)
    k = (1000000007 + x - 1) % 1000000007;
  else
    k = (1000000007 + x + 1) % 1000000007;
  k = (k * pp(3, 1000000007 - 2)) % 1000000007;
  cout << k << '/' << x << endl;
  return 0;
}
