#include <bits/stdc++.h>
using namespace std;
long long power(long long a, long long b) {
  long long r = 1;
  while (b != 0) {
    if (b % 2 != 0) {
      r = r * a;
      r %= 1000000007;
    }
    a = a * a;
    a = a % 1000000007;
    b = b / 2;
  }
  return r;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int t = 1;
  while (t--) {
    int k;
    cin >> k;
    long long ast[k + 1];
    bool f = true;
    long long u = 2, p, q;
    for (int i = 1; i <= k; i++) {
      cin >> ast[i];
      if (ast[i] % 2 == 0) {
        f = false;
      }
      u = power(u, ast[i]);
    }
    u = u * power(2, 1000000007 - 2);
    u %= 1000000007;
    if (f == false) {
      p = (u + 1) * (power(3, 1000000007 - 2));
      p %= 1000000007;
      cout << p << "/" << u << endl;
    } else {
      p = ((u - 1) % 1000000007) * (power(3, 1000000007 - 2));
      p %= 1000000007;
      cout << p << "/" << u << endl;
    }
  }
}
