#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const int N = 1e5;
long long n, arr[N + 2], sum;
long long bigmod(long long b, long long p, long long mod) {
  long long ret = 1LL;
  while (p) {
    if (p & 1) ret = (ret * b) % mod;
    b = (b * b) % mod;
    p /= 2;
  }
  return ret;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> arr[i];
  long long up = 2, dw = 1;
  int f = 0;
  for (int i = 1; i <= n; i++) {
    if (arr[i] % 2 == 0) f = 1;
    up = bigmod(up, arr[i], mod) % mod;
  }
  up = (up * bigmod(2, mod - 2, mod)) % mod;
  dw = up;
  if (f)
    up = (up + 1) % mod;
  else
    up = (up - 1 + mod) % mod;
  up = (up * bigmod(3, mod - 2, mod)) % mod;
  cout << up << "/" << dw << endl;
  return 0;
}
