#include <bits/stdc++.h>
using namespace std;
const int P = 1e9 + 7;
const int P2 = 1e9 + 6;
long long a, n = 1, p, q, inv3;
bool f, f2;
long long P_pow(long long a, int b) {
  long long c = 1;
  for (; b; b >>= 1) {
    if (b & 1) c = c * a % P;
    a = a * a % P;
  }
  return c;
}
int main() {
  int k, i;
  scanf("%d", &k);
  for (i = 1; i <= k; i++) {
    scanf("%I64d", &a);
    if (!(a & 1)) f = 1;
    if (a > 1) f2 = 1;
    a %= P2;
    n = n * a % P2;
  }
  if (!f2) {
    puts("0/1");
    return 0;
  }
  n = (n - 1 + P2) % P2;
  q = P_pow(2, n);
  inv3 = P_pow(3, P2 - 1);
  p = q;
  if (f)
    p = (p + 1) % P;
  else
    p = (p - 1 + P) % P;
  p = p * inv3 % P;
  printf("%I64d/%I64d", p, q);
}
