#include <bits/stdc++.h>
using namespace std;
int k;
long long a, n, x, y, even = -1;
long long modPow(long long a, long long n, long long m) {
  if (n == 0) return 1;
  if (n % 2 == 0) {
    return modPow((a * a) % m, n / 2, m);
  }
  return (a * modPow(a, n - 1, m)) % m;
}
int main() {
  scanf("%d", &k);
  n = 1LL;
  while (k--) {
    scanf("%I64d", &a);
    if (a % 2 == 0) {
      even = 1;
    }
    a = a % (1000000007 - 1);
    n = (n * a) % (1000000007 - 1);
  }
  n--;
  if (n < 0) {
    n += (1000000007 - 1);
  }
  y = modPow(2, n, 1000000007);
  x = y + even;
  x = (x * modPow(3, 1000000007 - 2, 1000000007)) % 1000000007;
  cout << x << "/" << y << endl;
  return 0;
}
