#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1000000007;
int N;
long long inv2, inv3, p, q;
bool even;
long long fast_exp(long long B, long long E) {
  if (E == 0LL) return 1LL;
  long long tmp = fast_exp(B, E >> 1);
  tmp = (tmp * tmp) % MOD;
  if (E % 2LL == 1) tmp = (tmp * B) % MOD;
  return tmp;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> N;
  inv2 = fast_exp(2LL, MOD - 2LL);
  inv3 = fast_exp(3LL, MOD - 2LL);
  q = 2LL;
  for (int i = 0; i < N; i++) {
    long long A;
    cin >> A;
    if (A % 2LL == 0) even = true;
    q = fast_exp(q, A);
  }
  q = (q * inv2) % MOD;
  if (even)
    p = (q + 1LL) % MOD;
  else
    p = (q - 1LL) % MOD;
  p = (p * inv3) % MOD;
  cout << p << "/" << q << "\n";
  return 0;
}
