#include <bits/stdc++.h>
using namespace std;
const int INF = 0x7f7f7f7f;
const int MAXN = 1e6 + 111;
const int MOD = 1e9 + 7;
long long power(long long base, long long p) {
  long long ret = 1;
  while (p) {
    if (p & 1) ret = ret * base % MOD;
    base = base * base % MOD;
    p >>= 1;
  }
  return ret;
}
int main() {
  int k;
  cin >> k;
  long long x, n = 2;
  bool odd = 1;
  while (k--) {
    cin >> x;
    if (!(x & 1)) odd = 0;
    n = power(n, x);
  }
  n = n * power(2, MOD - 2) % MOD;
  cout << (n + (odd ? -1 : 1)) * power(3, MOD - 2) % MOD << '/' << n << '\n';
  return 0;
}
