#include <bits/stdc++.h>
using namespace std;
using LL = long long;
constexpr int N = 1e5 + 5;
constexpr LL MOD = 1e9 + 7;
LL power(LL a, LL b) {
  LL rv = 1;
  while (b) {
    if (b & 1) rv = rv * a % MOD;
    a = a * a % MOD;
    b /= 2;
  }
  return rv;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int k;
  cin >> k;
  LL n = 1;
  int parity = 1;
  for (int i = 0; i < k; i++) {
    LL x;
    cin >> x;
    x %= MOD - 1;
    n *= x;
    n %= MOD - 1;
    if (!(x & 1)) parity = 0;
  }
  n = (n - 1 + MOD - 1) % (MOD - 1);
  int d = parity == 0 ? 1 : -1;
  LL num = power(2, n);
  LL den = num;
  num = (num + d + MOD) % MOD;
  (num *= power(3, MOD - 2)) %= MOD;
  cout << num << "/" << den << endl;
}
